Category Archives: technologies

Building Blocks – Part I: Build your own #PrivateCloud

Posted on by

Part 1 -> The Building Block Approach

As 2011 wraps up and I have a little time at home over the holidays, I’ve been reflecting on some of the customer projects I’ve worked on over the past year. Cloud computing and EMC’s vision for the “Journey to the Private Cloud” have been hot topics this year and of the various projects I’ve worked on this past year, one stands out to me as something that could be used as a blueprint for others who want to deploy their own Private Cloud but may not know how to start.

I have been working with a customer with approximately 10,000 servers that support their business and for all intents had zero virtualization as recent as 2010.  As most customers already know, they thought it would be good to begin virtualizing their environment to drive up asset utilization and flexibility while bringing down costs.  In the past, they’ve experimented with multiple server virtualization solutions (such as VMWare ESX and Microsoft Hyper-V) with limited success and had all but abandoned the idea.  A change in leadership in late 2010 brought a top-down initiative to virtualize wherever possible, but in order to instill confidence in virtualized environments within the various business units, the virtual infrastructure needed to be reliable and performant.

The customer spent the latter half of 2010 looking at their existing physical environment, finding that about 80% of the 10,000 servers were various application, file, and web servers; the remaining 20% being various database servers (mostly MS SQL).  Moving an infrastructure this large into a Private Cloud model would take several years and, further adding to the challenge, the DBA teams were particularly wary about virtualizing their database servers.  That said, the newly formed Virtualization and Cloud team set a goal of virtualizing the approximately 8,000 non-database servers over 36 months, starting out with dev/test and gradually adding production and tier-1 applications until only the database servers remained on physical infrastructure.  They believe that if they prove success with virtualization during this first 3 years, the DBAs will be more willing to begin virtualizing their systems, plus there should be more knowledge and tools in the public domain for managing virtual database instances by then.

To accomplish all of their goals, the customer leveraged some experience that individual team members had gained from prior environments to come up with a Building Block based deployment.  I worked with them to finalize the design and sizing for the each Building Block and throughout the year have helped analyze the performance of the deployed infrastructure to help determine how the Building Blocks can be optimized further.  Through the next several posts, I will explain the Building Block approach, detailing the benefits, some of the considerations, and some thoughts around sizing.  I hope that this information will be useful to others.  The content is mostly vendor agnostic except for some example data that uses EMC specific storage best practices.

Part 1 -> The Building Block Approach

Category: efficiency, solutions, technologies | Tags: , , , , , , , , , , , , , , , , , , , , , ,

Defining RTO and RPO for your data…

Posted on by

Do you have a clearly defined Recovery Point Objective (RPO) for your data?  What about a clearly defined Recovery Time Objective (RTO)?

One challenge I run in to quite often is that, while most customers assume they need to protect their data in some way, they don’t have clear cut RPO and RTO requirements, nor do they have a realistic budget for deploying backup and/or other data protection solutions.  This makes it difficult to choose the appropriate solution for their specific environment.  Answering the above questions will help you choose a solution that is the most cost effective and technically appropriate for your business.

But how do you answer these questions?

First, let’s discuss WHY you back up… The purpose of a backup is to guarantee your ability to restore data at some point in the future, in response to some event.  The event could be inadvertent deletion, virus infection, corruption, physical device failure, fire, or natural disaster.  So the key to any data protection solution is the ability to restore data if/when you decide it is necessary.  This ability to restore is dependent on a variety of factors, ranging from the reliability of the backup process, to the method used to store the backups, to the media and location of the backup data itself.  What I find interesting is that many customers do not focus on the ability to restore data; they merely focus on the daily pains of just getting it backed up.  Restore is key! If you never intend to restore data, why would you back it up in the first place?

What is the Risk?

USA Today published an article in 2006 titled “Lost Digital Data Cost Businesses Billions” referencing a whole host of surveys and reports showing the frequency and cost to businesses who experience data loss.

Two key statistics in the article stand out.

  • 69% of business people lost data due to accidental deletion, disk or system failure, viruses, fire or another disaster
  • 40% Lost data two or more times in the last year

Flipped around, you have at least a 40% chance of having to restore some or all of your data each year.  Unfortunately, you won’t know ahead of time what portion of data will be lost.  What if you can’t successfully restore that data?

This is why one of my coworkers refuses to talk to customers about “Backup Solutions”, instead calling them “Restore Solutions”, a term I have adopted as well.  The key to evaluating Restore Solutions is to match your RPO and RTO requirements against the solution’s backup speed/frequency and restore speed respectively.

Recovery Point Objective (RPO)

Since RPO represents the amount of data that will be lost in the event a restore is required, the RPO can be improved by running a backup job more often.  The primary limiting factor is the amount of time a backup job takes to complete.  If the job takes 4 hours then you could, at best, achieve a 4-hour RPO if you ran backup jobs all day.  If you can double the throughput of a backup, then you could get the RPO down to 2 hours.  In reality, CPU, Network, and Disk performance of the production system can (and usually is) affected by backup jobs so it may not be desirable to run backups 24 hours a day.  Some solutions can protect data continuously without running a scheduled job at all.

Recovery Time Objective (RTO)

Since RTO represents the amount of time it takes to restore the application once a recovery operation begins, reducing the RTO can be achieved by shortening the time to begin the restore process, and speeding up the restore process itself.  Starting the restore process earlier requires the backup data to be located closer to the production location.  A tape located in the tape library, versus in a vault, versus at a remote location, for example affects this time.  Disk is technically closer than tape since there is no requirement to mount the tape and fast forward it to find the data.  The speed of the process itself is dependent on the backup/restore technology, network bandwidth, type of media the backup was stored on, and other factors.  Improving the performance of a restore job can be done one of two ways – increase network bandwidth or decrease the amount of data that must be moved across the network for the restore.

This simple graph shows the relationship of RTO and RPO to the cost of the solution as well as the potential loss.The values here are all relative since every environment has a unique profit situation and the myriad backup/restore options on the market cover every possible budget.

Improving RTO and/or RPO generally increases the cost of a solution.  This is why you need to define the minimum RPO and RTO requirements for your data up front, and why you need to know the value of your data before you can do that.  So how do you determine the value?

Start by answering two questions…

How much is the data itself worth?  

If your business buys or creates copyrighted content and sells that content, then the content itself has value.  Understanding the value of that data to your business will help you define how much you are willing to spent to ensure that data is protected in the event of corruption, deletion, fire, etc.  This can also help determine what Recovery Point Objective you need for this data, ie: how much of the data can you lose in the event of a failure.

If the total value of your content is $1000 and you generate $1 of new content per day, it might be worth spending 10% of the total value ($100) to protect the data and achieve an RPO of 24 hours.  Remember, this 10% investment is essentially an insurance policy against the 40% chance of data loss mentioned above which could involve some or all of your $1000 worth of content.  Also keep in mind that you will lose up to 24 hours of the most recent data ($1 value) since your RPO is 24 hours.  You could implement a more advanced solution that shortens the RPO to 1 hour or even zero, but if the additional cost of that solution is more than the value of the data it protects, it might not be worth doing.  Legal, Financial, and/or Government regulations can add a cost to data loss through fines which should also be considered.  If the loss of 24 hours of data opens you up to $100 in fines, then it makes sense to spend money to prevent that situation.

How much value does the data create per minute/hour/day?

Whether or not your data itself has value on it’s own, the ability to access it may have value.  For example, If your business sells products or services through a website and a database must be online for sales transactions to occur, then an outage of that database causes loss of revenue.  Understanding this will help you define a Recovery Time Objective, ie: for how long is it acceptable for this database to be down in the event of a failure, and how much should you spend trying to shorten the RTO before you get diminishing returns.

If you have a website that supports company net profits of $1000 a day,  it’s pretty easy to put together an ROI for a backup solution that can restore the website back into operation quickly.  In this example, every hour you save in the restore process prevents $42 of net loss.  Compare the cost of improving restore times against the net loss per hour of outage.  There is a crossover point which will provide a good return on your investment.

Your vendor will be happy when you give them specific RPO and RTO requirements.

Nothing derails a backup/recovery solution discussion quicker than a lack of requirements.  Your vendor of choice will most likely be happy to help you define them but it will help immensely if you have some idea of your own before discussions start.  There are many different data protection solutions on the market and each has it’s own unique characteristics that can provide a range of RPO and RTO’s as well as fit different budgets. Several vendors, including EMC, have multiple solutions of their own — one size definitely does not fit all.  Once you understand the value of your data, you can work with your vendor(s) to come up with a solution that meets your desired RPO and RTO while also keeping a close eye on the financial value of the solution.

Category: solutions, technologies | Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Does EMC FASTCache work with Exchange?

Posted on by

Short Answer: Yes!

In my dealings with customers I’ve been requesting performance data from their storage systems whenever I can to see how different applications and environments react to new features. Today I’m going to give you some more real-world data, straight from a customer’s production EMC NS480.

I’ve pulled various stats out of Analyzer for this customer’s Exchange server, which has 3 mail databases totaling about 1TB of mail stored on the NS480 via FibreChannel connect. Since this customer is not extremely large (similar to most of our customers) they are using this NS480 for pretty much everything from VMWare, SQL, and Exchange, to NAS, web/app content, and Business Intelligence systems. There is about 30TB of block data and another 100TB of NAS data. FASTCache is enabled for all LUNs and Pools with just 183GB of usable FASTCache space (4 x 100GB SSDs). So in this environment, with a modest amount of FASTCache and very mixed workload, how does Exchange fare?

Let’s first take a look at the Exchange workload itself for a 24 hour period: (Note: There were no reads from the Exchange log LUNs to speak of so I left that out of this analysis.)

Total Read IOPS for the 3 databases: (the largest peak is a result of database maintenance jobs and the smaller peaks are due to backup jobs) Here it’s tough to see due to the maintenance and backup peaks, but production IO during the work day is about 200-400IOPS. By the way, a source-deduplicating incremental-forever backup technology, such as Avamar, could drastically reduce the IO Load and duration of the nightly backup

Total Write IOPS for the 3 databases: Obviously more changes to the database occurring during the work day.

Total Write IOPS for the 3 Log files: Log data is typically cached easily in the SP cache so FAST Cache isn’t terribly required here but I’m including it to show whether there is any value to using FASTCache with Exchange logs.

Now let’s look at the FASTCache hit ratios for this same set of data: (average of all 3 DBs)

First, the Read Activity: Here you can see that aside from the maintenance and backup jobs, FASTCache is servicing 70-90% of the Read IOPs. Keep in mind that a FASTCache miss could still be a Cache Hit if the data is in SP Cache. What’s interesting about this is that it looks like the nightly maintenance job is pushing the highest load.

And the Write Activity: The beauty of EMC’s FASTCache implementation being a read/write cache, the benefit extends beyond just read IO. Here you see that FASTCache is servicing 60-80% of the writes for these Exchange Databases. That’s a huge load off the backend disks.

And the Log Writes: Since Log writes are usually not a performance problem, I would say that FASTCache is not necessary here, and the average 30% hit ratio shown here is not great. If you wanted to spend the time to tune FASTCache a bit, you might consider disabling FASTCache for Log LUNs to devote the FASTCache capacity to more cache friendly workloads.

All in all you can see that for the database data, FASTCache is servicing a significant portion of the user generated workload, reducing the backend disk load and improving overall performance.

Hopefully this gives you a sense of what FASTCache could do for your Exchange environment, reducing backend disk workload for reads AND writes. I must reiterate, since an SP Cache hit is shown as a FASTCache miss, an 80% FASTCache hit ratio does not mean that 20% of the IOs are hitting disk. To illustrate this, I’ve graphed the sum of SP Cache Hits and FAST Cache Hits for a single database. You can see that in many cases we’re hitting a total of 100% cache hits.

Most interesting is the backup window where SP Cache is really handling a huge amount of the load. This is actually due to the Prefetch algorithms kicking in for the sequential read profile of a backup, something CX/VNX is very good at.

Category: efficiency, problems, solutions, technologies | Tags: , , , , , , , , , , , , , , , , , ,

EMCWorld 2011 Announcements

Posted on by

After flying into Las Vegas this morning, checking in to the Cosmopolitan Hotel with 2000+ other EMCer’s, and taking the bus to the Venetian, I’m finally settling in a bit.  I watched Pat Gelsinger’s keynote via recorded video on Facebook.com/EMCCorp to get caught up on what I’ve missed so far and there was more in there than I expected.

Buried in the hour long keynote about EMC’s portfolio and how it aligns with Big Data and Cloud Computing were several important announcements.

  1. Atmos 2.0 – Improved Performance, Compatibility with Amazon S3, and a Windows native client called GeoDrive.   Atmos already offered a client for Redhat Linux which joined the Redhat client into the Atmos Cloud for direct access to objects/files.  GeoDrive provides native file access to the Atmos cloud for Windows clients.  This is particularly useful for supporting legacy applications that have not (or cannot) be modified to use the Atmos RESTful API.
  2. Isilon NL108 – The new NearLine nodes contain 108TB of disk space in each node, and this increase in node capacity has similarly increased the maximum filesystem size of an Isilon cluster from 10PB to 15PB (In a SINGLE filesystem..  And yes, that’s PetaBytes).
  3. Project Lightning – PCIe based FLASH caching adapters for Servers.  Intended to work in conjunction with FASTVP to cache data at the server and possibly distributed across servers.
  4. EMC Hadoop (aka Greenplum HD) – EMC supplied and supported Hadoop distribution which can be acquired as software or as an appliance, similar to Greenplum.     

Lot’s more to come.  Chuck Hollis just sat down here so it’s time to socialize..

Category: announcements, technologies | Tags: , , , , , , , , , , ,

If You Are Using SSDs, You Should Be Encrypting

Posted on by

I saw the following article come across Twitter today.

http://www.zdnet.com/blog/storage/ssd-security-the-worst-of-all-worlds/1326

In it, Robin Harris describes the issues around data recovery and secure erasure specific to SSD disks.  In layman’s terms, since SSDs do all sorts of fancy things with writes to increase longevity and performance, disk erasure is nearly impossible using normal methods, and forensic or malicious data recovery is quite easy.  So if you have sensitive data being stored on SSDs, that data is at risk of being read by someone, some day, in the future.  It seems that pretty much the only way to mitigate this risk is to use encryption at some level outside the SSD disk itself.

Did you know that EMC Symmetrix VMAX offers data-at-rest encryption that is completely transparent to hosts and applications, and has no performance impact?  With Symmetrix D@RE, each individual disk is encrypted with a unique key, managed by a built-in RSA key manager, so disks are unreadable if removed from the array.   Since the data is encrypted as the VMAX is writing to the physical disk, attempting to read data off an individual disk without the key is pointless, even for SSD disks.

The beauty of this feature is that it’s set-it-and-forget it.  No management needed, it’s enabled during installation and that’s it.  All disks are encrypted, all the time.

  • Ready to decomm an old array and return it, trade it, or sell it?  Destroy the keys and the data is gone.  No need for an expensive Data Erasure professional services engagement.
  • Failed disk replaced by your vendor?  No need for special arrangements with your vendor to keep those disks onsite, or certify erasure of a disk every time one is replaced.  The key stays with the array and the data on that disk is unreadable.

If you have to comply with PCI and/or other compliance rules that require secure erasure of disks, you should consider putting that data on a VMAX with data-at-rest encryption.

Now, What if you have an existing EMC storage system and the same need to encrypt data?  You can encrypt at the volume level with PowerPath Encryption.  PowerPath encrypts the data at the host with a unique key managed by an RSA Key Manager.  And it works with the non-EMC arrays that PowerPath supports as well.

Under normal circumstances, PowerPath Encryption does have some level of performance impact to the host however HBA vendors, such as Emulex, are now offering HBAs with encryption offload that works with PowerPath.  If you combine PowerPath Encryption with Emulex Encryption HBAs, you get in-flight AND at-rest encryption with near-zero performance impact.

  • Do you replicate your sensitive data to a 3rd party remote datacenter for business continuity?  PowerPath Encryption prevents unauthorized access to the data because no host can read it without the proper key.
Category: problems, solutions, technologies | Tags: , , , , , , , , , , , , , , ,

Real World EMC FASTVP and FASTCache results!

Posted on by

I have a customer who just recently upgraded their EMC Celerra NS480 Unified Storage Array (based on Clariion CX4-480) to FLARE30 and enabled FASTCache across the array, as well as FASTVP automated tiering for a large amount of their block data.  Now that it’s been configured and the customer has performed a large amount of non-disruptive migrations of data from older RAID groups and VP pools into the newer FASTVP pool, including thick-to-thin conversions, I was able to get some performance data from their array and thought I’d share these results.

This is Real-World data

This is NOT some edge case where the customer’s workload is perfect for FASTCache and FASTVP and it’s also NOT a crazy configuration that would cost an arm and a leg.  This is a real production system running in a customer datacenter, with a few EFDs split between FASTCache and FASTVP and some SATA to augment capacity in the pool for their existing FC based LUNS.  These are REAL results that show how FASTVP has distributed the IO workload across all available disks and how a relatively small amount of FASTCache is absorbing a decent percentage of the total array workload.

This NS480 array has nearly 480 drives in total and has approximately 28TB of block data (I only counted consumed data on the thin LUNs) and about 100TB of NAS data.  Out of the 28TB of block LUNs, 20TB is in Virtual Pools, 14TB of which is in a single FASTVP Pool.  This array supports the customers’ ERP application, entire VMWare environment, SQL databases, and NAS shares simultaneously.

In this case FASTCache has been configured with just 183GB of usable capacity (4 x 100GB EFD disks) for the entire storage array (128TB of data) and is enabled for all LUNs and Pools.  The graphs here are from a 4 hour window of time after the very FIRST FASTVP re-allocation completed using only about 1 days’ worth of statistics.  Subsequent re-allocations in the FASTVP pool will tune the array even more.

FASTCache

First, let’s take a look at the array as a whole, here you can see that the array is processing approximately ~10,000 IOPS through the entire interval.

FASTCache is handling about 25% of the entire workload with just 4 disks.  I didn’t graph it here but the total array IO Response time through this window is averaging 2.5 ms.  The pools and RAID Groups on this array are almost all RAID5 and the read/write ratio averages 60/40 which is a bit write heavy for RAID5 environments, generally speaking.

If you’ve done any reading about EMC FASTCache, you probably know that it is a read/write cache.  Let’s take a look at the write load of the array and see how much of that write load FASTCache is handling.  In the following graph you can see that out of the ~10,000 total IOPS, the array is averaging about 2500-3500 write IOPS with FASTCache handling about 1500 of that total.

That means FASTCache is reducing the back-end writes to disk by about 50% on this system.  On the NS480/CX4-480, FASTCache can be configured with up to 800GB usable capacity, so this array could see higher overall performance if needed by augmenting FASTCache further.  Installing and upgrading FASTCache is non-disruptive so you can start with a small amount and upgrade later if needed.

FASTVP and FASTCache Together

Next, we’ll drill down to the FASTVP pool which contains 190 total disks (5 x EFD, 170 x FC, and 15 x SATA).  There is no maximum number of drives in a Virtual Pool on FLARE30 so this pool could easily be much larger if desired.  I’ve graphed the IOPS-per-tier as well as the FASTCache IOPS associated with just this pool in a stacked graph to give an idea of total throughput for the pool as well as the individual tiers.

The pool is servicing between 5,000 and 8,000 IOPS on average which is about half of the total array workload.  In case you didn’t already know, FASTVP and FASTCache work together to make sure that data is not duplicated in EFDs.  If data has been promoted to the EFD tier in a pool, it will not be promoted to FASTCache, and vise-versa.  As a result of this intelligence, FASTCache acceleration is additive to an EFD-enabled FASTVP pool.   Here you can see that the EFD tier and FASTCache combined are servicing about 25-40% of the total workload, the FC tier another 40-50%, and the SATA tier services the remaining IOPS.  Keep in mind that FASTCache is accelerating IO for other Pools and RAID Group LUNs in addition to this one, so it’s not dedicated to just this pool (although that is configurable.)

FASTVP IO Distribution

Lastly, to illustrate FASTVP’s effect on IO distribution at the physical disk layer, I’ve broken down IOPS-per-spindle-per-tier for this pool as well.  You can see that the FC disks are servicing relatively low IO and have plenty of head room available while the EFD disks, also not being stretched to their limits, are servicing vastly more IOPS per spindle, as expected.  The other thing you may have noticed here is that the EFDs are seeing the majority of the workload’s volatility, while the FC and SATA disks have a pretty flat workload over time.  This illustrates that FASTVP has placed the more bursty workloads on EFD where they can be serviced more effectively.

Hopefully you can see here how a very small amount of EFDs used with both FASTCache and FASTVP can relieve a significant portion of the workload from the rest of the disks.  FASTCache on this system adds up to only 0.14% of the total data set size and the EFD tier in the FASTVP pool only accounts for 2.6% of the total dataset in that pool.

What do you think of these results?  Have you added FASTCache and/or FASTVP to your array?  If so, what were your results?

Category: efficiency, solutions, technologies | Tags: , , , , , , , , , , , , , , , , , ,

Say Hello to EMC VNX7500

Posted on by

I got these pictures from one of my customers who completed install of two new EMC VNX7500 arrays.  It may be hard to tell but each of these systems host 21 x EFD drives and over 500 x SAS drives in a single rack.  Building on EMC’s promise of efficiency, each of these VNX arrays are delivering over 60,000 heavy-write host IOPS while providing 130TB of usable capacity in a single rack, consuming less power than the 4 servers in the neighboring rack.  Combined, these two arrays provide 260TB usable of extremely high performance storage to host many hundreds of production virtual servers.

VNX7500s installed and running

 

Category: efficiency, technologies | Tags: , , , ,

Auto-Tiering, Cloud Storage, and Risk-Free Thin Pools

Posted on by

Some customers are afraid of thin provisioning…

Practically every week I have discussions with customers about leveraging thin provisioning to reduce their storage costs and just as often the customer pushes back worried that some day, some number of applications, for some reason, will suddenly consume all of their allocated space in a short period of time and cause the storage pool to run out of space.  If this was to happen, every application using that storage pool will essentially experience an outage and resolving the problem requires allocating more space to the pool, migrating data, and/or deleting data, each of which would take precious time and/or money.  In my opinion, this fear is the primary gating factor to customers using thin provisioning.  Exacerbating the issue, most large organizations have a complex procurement process that forces them to buy storage many months in advance of needing it, further reducing the usefulness of thin provisioning.  The IT organization for one of my customers can only purchase new storage AFTER a business unit requests it and approved by senior management; and they batch those requests before approving a storage purchase.  This means that the business unit may have to wait months to get the storage they requested.

This same customer recently purchased a Symmetrix VMAX with FASTVP and will be leveraging sub-LUN tiering with SSD, FC, and SATA disks totaling over 600TB of usable capacity in this single system.  As we began design work for the storage array the topic of thin provisioning came up and the same fear of running out of space in the pool was voiced.  To prevent this, the customer fully allocates all LUNs in the pool up front which prevents oversubscription.  It’s an effective way to guarantee performance and availability but it means that any free space not used by application owners is locked up by the application server and not available to other applications.  If you take their entire environment into account with approximately 3PB of usable storage and NO thin provisioning, there is probably close to $1 million in storage not being used and not available for applications.  If you weigh the risk of an outage causing the loss of several million dollars per hour of revenue, the customer has decided the risks outweigh the potential savings.  I’ve seen this decision made time and again in various IT shops.

Sub-LUN Tiering pushes the costs for growth down

I previously blogged about using cloud storage for block storage in the form of Cirtas BlueJet and how it would not be to much of a stretch to add this functionality to sub-LUN tiering software like EMC’s FASTVP to leverage cloud storage as a block storage tier as shown in this diagram.

Let’s first assume the customer is already using FASTVP for automated sub-LUN tiering on a VMAX.  FASTVP is already identifying the hot and cold data and moving it to the appropriate tier, and as a result the lowest tier is likely seeing the least amount of IOPS per GB.  In a VMAX, each tier consists of one or more virtual provisioned pools, and as the amount of data stored on the array grows FASTVP will continually adjust, pushing the hot data up to higher tiers and cold data down to the lower tiers  The cold data is more likely to be old data as well so in many cases the data sort of ages down the tiers over time and its the old/least used portion of the data that grows.  Conceptually, the only tier you may have to expand is the lowest (ie: SATA) when you need more space.  This reduces the long term cost of data growth which is great.  But you still need to monitor the pools and expand them before they run out of space, or an outage may occur.  Most storage arrays have alerts and other methods to let you know that you will soon run out of space.

Risk-Free Thin Provisioning

What if the storage array had the ability automatically expand itself into a cloud storage provider, such as AT&T Synaptic, to prevent itself from running out of space?  Technically this is not much different from using the cloud as a tier all it’s own but I’m thinking about temporary use of a cloud provider versus long term.  The cloud provider becomes a buffer for times when the procurement process takes too long, or unexpected growth of data in the pool occurs.  With an automated tiering solution, this becomes relatively easy to do with fairly low impact on production performance.  In fact, I’d argue that you MUST have automated tiering to do this or the array wouldn’t have any method for determining what data it should move to the cloud.  Without that level of intelligence, you’d likely be moving hot data to the cloud which could heavily impact performance of the applications.

Once the customer is able to physically add storage to the pool to deal with the added data, the array would auto-adjust by bringing the data back from the cloud freeing up that space.  The cloud provider would only charge for the transfer of data in/out and the temporary use of space.  Storage reduction technologies like compression and de-duplication could be added to the cloud interface to improve performance for data stored in the cloud and reduce costs.  Zero detect and reclaim technologies could also be leveraged to keep LUNs thin over time as well as prevent the movement of zero’d blocks to the cloud.

Using cloud storage as a buffer for thin provisioning in this way could reduce the risk of using thin provisioning, increasing the utilization rate of the storage, and reducing the overall cost to store data.

What do you think?  Would you feel better about oversubscribing storage pools if you had a fully automated buffer, even if that buffer cost some amount of money in the event it was used?

Category: efficiency, problems, solutions, technologies | Tags: , , , , , , , , , , , , , , ,

Test Environments for Parents?

Posted on by

So I’ve been a father for about 6 months now and over that time I’ve found that the life of a parent is essentially a series of experiments with real life consequences.  Every day I wonder whether I’m doing the right thing for my daughter and when I have to make a decision about pretty much anything related to her, I must weigh the possible consequences of each option.

Case in point, I was feeding my daughter last night at 1am and my mind started wandering, as it usually does–this time about my daughter’s handedness.  My wife and I believe she is left-handed, partly because we both are, and partly because she seems to favor her left hand, but it’s really too early to tell.  Very early on, we found that she sleeps best at night when she’s swaddled nice and tight, but after a couple of months she stopped sleeping easily unless we kept just her left arm free, another check in the left-handed box.  I now leave her left arm free every time I swaddle her, without exception, which leads me to the concern I suddenly felt last night —

Does keeping my daughters right arm tight in the swaddle stifle the development of that arm?  Could she possibly be right-handed but we are only allowing the left arm to develop?  Should I leave her right arm out next time?  What is the consequence of continuing with the status-quo?  She sleeps well with the status-quo, which means I sleep well.  What is the consequence of switching arms?  Would she have trouble sleeping and thus keep me up all night if I switch her arm?  Or would she still sleep well and prove over time that she’s actually right-handed?  Should I feed her apples or the chicken dinner?  How do you handcuff a one-armed man?

The challenge here is that I don’t have a test-lab (aka: test baby) to experiment with different swaddling techniques or foods in order to answer these questions?  As parents, we (the proverbial “we”) are constantly experimenting with real-live children and hoping we don’t screw up.  What’s worse is that humans are all unique, so even your first child doesn’t necessarily teach you everything you need to know for your second.

Out in the business world, there are test environments for all sorts of systems, software, electronics, cars, etc where experiments are tested and proven first, then put in place in production environments.  The consequence for screwing up most of these systems?  Somebody, somewhere, may not be able to buy an iPhone that day.  The consequence for messing up in parenting?  Ruining our children, ruining our own lives, or both.  Sometimes when I have a stressful day at work, coming home to take care of my daughter puts things into perspective.

Category: problems, technologies | Tags: , , , , , , , , , , , ,

Saving $90,000 per minute with VMAX Federated Live Migration

Posted on by

One of the customers I work with regularly has a set of key MS SQL databases totaling over 100TB in size which process transactions for their customer facing systems. If these databases are down, no transactions can be processed and customers looking to spend money will go elsewhere. The booking rate related to these databases is ~$90,000 per minute, all day, every day.

Today these databases live on Symmetrix DMX storage which has been very reliable and performant. As happens in an IT world, some of these Symmetrix systems are getting long in the tooth and we are working on refreshing several older DMX systems into fewer, newer VMAX systems. Aside from the efficiency and performance benefits of sub-LUN tiering (EMC FASTVP), and the higher scalability of VMAX vs DMX as well as pretty much any other storage array on the market, EMC has added another new feature to VMAX that is particularly advantageous to this particular customer — Federated Live Migration

Tech Refresh and Data Migrations:

Tech Refresh is a fact of life and data migrations, as a result are common place. The challenge with a data migration is finding a workable process and then shoehorning that process into existing SLAs and maintenance windows. In general, data migrations are disruptive in some way or another, and the level of disruption depends on the technology used and the type of migration. EMC has a long list of migration tools that cover our midrange storage systems, NAS systems, as well as high-end Symmetrix arrays. The downside with these and other vendors’ migration tools is that there is some level of downtime required.

There are 3 basic approaches:

  1. Highest Amount of Downtime:
    • Take system down, copy data, reconfigure system, bring system online
  2. Less Downtime:
    • Copy Data, Take system down, copy recent changes, reconfigure system, bring system online (EMC Open Replicator, EMCopy, RoboCopy, Rsync, EMC SANCopy, etc)
  3. Even Less Downtime:
    • Set up new storage to proxy old storage, reconfigure system, serve data while copying in the background. (EMC Celerra CDMS, EMC Symmetrix Open Replicator)
    • (Traditional virtualization systems like Hitachi USP/VSP, IBM SVC, etc are similar to this as well since you must take some level of downtime to get hosts configured through the virtualization layer, after which you can non-disruptively move data).

Common theme in all 3? Downtime!

Non-Disruptive Migrations are becoming more realistic:

A while ago now, EMC added a feature to PowerPath called Migration Enabler which is a way to non-disruptively migrate data between LUNs and/or Storage arrays from the host perspective. PowerPath Migration Enabler could also leverage storage based copy mechanisms and help with cut over. This is very helpful and I have multiple customers who have successfully migrated data with PPME. The challenge has been getting customers to upgrade to newer versions of PowerPath that include the PPME features they need for their specific environment. Software upgrades usually require some level of downtime, at least on a per-host basis, and we run into maintenance windows and SLAs again.

EMC Symmetrix Federated Live Migration (FLM)

For Symmetrix VMAX customers, EMC has added a new capability that could make data migrations easy as pie for many customers. With FLM, a VMAX can migrate data into itself from another storage array, and perform the host cutover, automatically, and non-disruptively. The VMAX does not have to be inserted in front of the other storage array, and there is no downtime required to reconfigure the host before or after the migration.

Federation is the key to non-disruptive migrations:

The way FLM works is really pretty simple. First, the host is connected to the new VMAX storage without removing the connectivity to the old storage. The VMAX is also connected to the old storage array directly (through the fabric in reality). The VMAX system then sets up a replication session for the devices owned by the host and begins copying data. This is all pretty straightforward. The smart stuff happens during the cut over process.

As you probably know, the VMAX is an Active/Active storage system, so all paths from a host to a LUN are active. Clariion, similar to most other midrange systems is an Active/Passive storage system. On Clariion, paths to the storage processor that owns the LUN are active, while paths to the non-owner are passive until needed. PowerPath and many other path management tools support both active/active and active/passive storage systems.

Symmetrix FLM leverages this active/passive support for the cut over. Essentially the old storage system is the “owning SP” before and during the migration. At cut over time, the VMAX essentially becomes the owning SP and it’s paths go active while the old paths go passive. PowerPath follows the “trespass” and the host keeps on chugging. To make this work, VMAX actually spoofs the LUN WWN and host ID, etc from the old array, so the host thinks it’s still talking to the old array. Filesystems and LVMs that signature and track LUNs based on WWN and/or Host ID are unaffected as a result. The cut over process is nothing more than a path change at the HBA level. The data copy and cut over are managed directly from the VMAX by an administrator.

Of course there are limitations… FLM initially supports only EMC Symmetrix DMX arrays as the source and requires PowerPath. From what I gather, this is not a technical limitation however, it’s just what EMC has tested and supports. Other EMC arrays will be supported later and I have no doubt it will support non-EMC arrays as a source as well.

Solving the $5 million problem:

Symmetrix Federated Live Migration became a signature feature in our VMAX discussions with the aforementioned customer because they know that for every minute their database is down, they lose $90,000 in revenue. Even with the fastest of the 3 traditional methods of migration, they would be down for up to an hour while 12 cluster nodes are rezoned to new storage, LUNs masked, drive letters assigned, etc. A reboot alone takes up to 30 minutes. 1 hour of downtime equates to $5,400,000 of lost revenue. By the way, that’s quite a bit more than the cost of the VMAX, and FLM is included at no additional license cost, so FLM just paid for the VMAX, and then some.

Category: problems, solutions, technologies | Tags: , , , , , , , , , , , , , , , , ,
← Newer Entries Older Entries →