StorageRap

Tiering is not for Chuck Norris

Separated at birth?

There have been some interesting discussions lately about storage tiering  And just because 3PAR beat most everybody else to the punch this week with our AO announcement, I think it's important to keep things in perspective - storage tiering does not solve everybody's problems. Here is my top 10 list of reasons some people don't want to embrace tiering: 

10. Chuck Norris does not need automation, automation needs Chuck Norris.

9.  The Chuck Norris of IT, Larry Ellison, says Exadata is the only tier you need.

8.  Chuck Norris & Larry Ellison will race to determine if tiering is good or evil.

7.  Heard it uses gerbils, which is unfair to guinea pigs.

6.  Chuck Norris got to Tom Georgens, he will get to you too.  

5.  Chuck Norris designed 3PAR's wide striping - who needs tiering?

4.  Chuck Norris already tunes my storage in his sleep.

3.  Larry Ellison is going to buy all the world's SSDs and corner the market.

2.  Waiting to hear if Chuck Norris will discuss tiering this week on InfoSmack. 

1.  Too busy celebrating Chuck Norris' 70th b-day today to care about tiering.

Why AO is a game changer

Yesterday, 3PAR announced Adaptive Optimization (AO), our solution for storage tiering and support for SSD flash drives. Here are the elements of this technology that I believe will have the most impact on customers and the rest of the industry.

1) Tiering works by making copies of data on lower cost, low-IOPS storage to high-IOPS storage - and back again.  Storage tiering has been associated with ILM, which assumed data is initially located on more expensive, high-IOPS storage and, as it ages and is accessed less frequently, is moved to lower-cost, low-IOPS storage. The perception that tiering implies fast to slow data migration was reinforced by Compellent with it's early entrant storage tiering technology, Data Progression.

The economic benefits of tiering are much more compelling if data is originally located on low-IOPS storage and then moved to high-IOPS storage when it becomes useful to do so. This reduces the amount of high-IOPS storage that needs to be purchased and reserves high-IOPS storage for the applications that need it the most. This model of promoting data to high-IOPS storage will replace the old model of data "trickling downhill to cheap storage."

2) Sub-volume tiering means high-IOPS storage can be reserved for high-IOPS work and effectively shared by the applications that need it the most.  AO copies data in 128 MB sub-volume regions that contain specific RAIDed volume slices. Many physical and virtual servers can have their volume's most active regions located in high-IOPS storage capacity at the same time.

Data redundancy is accomplished when AO reads data from it's source region and restripes it into a region on the target tier - using the RAID level of the target.  AO allows data to be protected by whatever RAID is appropriate for the tier and the data.  3PAR's chunklet architecture is maintained for SSDs, which means a SSDs in an InServ array can apply several different RAID levels simultaneously.  Every vendor's sub-volume tiering technology will be different, including the number of ways devices can be combined in RAID and how wide striping can be applied.

3) Tiering does not mean you have to buy SSDs to make it pay off.  Tiering is a cost-reduction technology.  One of the most obvious ways to reduce the cost of storage is to buy cheaper disks with higher capacity, such as SATA drives. 

The regions used by AO are the same on-disk structures that 3PAR uses for it's Dynamic Optimization (DO) software that re-levels volumes across disk drives in an InServ array.  A customer with all FC drives in an InServ array could take advantage of both AO and DO by increasing the capacity of an array with SATA drives, using Dynamic Optimization to redistribute their volumes across the SATA drives and then using FC drives as their high-IOPS AO tier. This way, they can continue to get the IO rates they expect, but reduce the cost of incremental capacity as they upgrade their system. 

4) The system determines what to move and how to move it. I/O density rate is a term that refers to how much data access occurs in a region over a given amount of time.  AO recognizes region candidates for tiering by their I/O density rates.  

Administrators control the AO participation for each volume by assigning them to an AO Profile and a QoS Gradient.  The profile is a short stack of device-RAID levels, such as SATA RAID 6, FC RAID 5(7+1) and SSD RAID5 (3+1). AO allows either  2 or 3 device RAID levels in the profile's stack.

The QoS gradient is a relative determinant of how quickly the volume will be acted upon.  I like to think of it as something like different viscosities for different fluids, but for storage.   AO today has three QoS gradients, performance, cost and balanced.

Back in Novemebr, Tony Asaro wrote about his discussions with HDS' storage customers regarding storage tiering.

Another discussion was around using policies to automate the process. One group was a bit concerned about automating this process but realized that, again, with PBs of data being stored that the only way to effectively implement intelligent tiered storage is via automation.  Additionally, it is not an all or nothing proposition.  You can select certain volumes and applications to implement and gain a comfort level before deploying more widely.  One of the key tenants of technology is to automate otherwise manually cumbersome processes.  We just need to get over that hurdle but we need to do so in a planned, considered and reasoned way.

By applying measured I/O density rates, AO profiles and QoS Gradients, 3PAR has taken the first major steps to automating storage tiering and removing the burden from administrators.

5) Tiering can and should scale out.  David Floyer from Wikibon wrote a good piece yesterday on our announcement where, among many things, he discussed how 3PAR is using smaller SSDs spread over more controllers:

....it spreads a small amount of SSD amongst the 3PAR engines so the IO’s aren’t all going to a single drive and sucking up a lot of bandwidth – it’s nicely balanced. Traditional implementations will use larger drive with more IO’s going to that drive. The part of the array with that drive will get more activity.

In practice we don’t think this will matter all that much because, for example, EMC’s V-Max has more bandwidth to play with than 3PAR and EMC uses its cache to transfer data between tiers to avoid bottlenecks. Nonetheless, on paper, the 3PAR implementation looks to be more efficient which means (in theory) it can do more with less flash. But nobody really knows yet.

3PAR storage arrays avoid I/O bottlenecks by incorporating tiny virtual storage elements (chunklets) and spreading the workload over as many devices and controllers as possible.  This approach differs from other vendors where smaller groups of resources are created and then combined into larger constructs that are more cumbersome to manage and tune than a single widely distributed storage span.  The same concepts apply to SSD integration, where InServ arrays accommodate multiples of many, smaller sized SSDs for scaling out high-IOPS tiers for those customers that may want to expand their use of AO in the future . 

3PAR Countdown: AO & SSDs

The news is here,  and    here,     and here.

3PAR announced its storage tiering technology today with the introduction of our Adaptive Optimization (AO) software and with support for flash SSDs. 

There's probably going to be a lot of discussion about storage tiering and AO in the weeks to come, so stay tuned.

FAST 0.5 exposes the changed game of storage

Chris Evans, the Storage Architect, had an unexpected analysis of EMC's FAST announcement today on his blog. The point he makes is that with FAST only being available on Intel-based array architectures - and not the DMX product line - that EMC has put themselves at a peer level with the rest of the industry.  As he says:

So what’s my point?  Well, simply this; EMC have legitimised the enterprise modular architecture characterised by V-Max.  This accepts that the future is commodity-based hardware with differentiation in software.  However, EMC are no longer the leaders in this field and are having to play catch up.

It's an interesting angle to be sure and it will be interesting to see how EMC's new platform works out after all the bluster and FUD over FAST is long forgotten.  EMC is going to busy in the years to come as they try to convert their DMX customers to v-Max customers.  All vendors go through this sort of thing when they introduce new architectures and even their most loyal customers are more or less forced to consider alternatives.  There is a lot of pressure on EMC all of a sudden to bring software to market that justifies the switch from the DMX -to v-MAX.  FAST has failed to do that so far.

EMC's pre-announcement of FAST earlier this year was presumably done to shore up their disappointing SSD sales - a tactic that apparently did not help their enterprise business much. But having played the FAST hand so early, they had no choice but to release FAST version 0.5 before the end of the year.  Will this help answer the questions about EMC's ability to develop enterprise level software for v_Max?  The answer has been loud and clear - let's wait until Fast 2.0.

EMC was way too early with SSDs and they just repeated the same mistake with FAST. Instead of creating an advantage for themselves, they allowed their competitors to observe what they are doing without applying any pressure. Instead, unexpectedly, the pressure is now on EMC to do better.  

Considering that 2009 was a year of backpedaling for EMC, I want to offer lessons in the art with this video:

Agility & Bull

3PAR has been designing and marketing it's agile storage for years. Recently, Hitachi started using the word "agile" in their messaging.  Imitation is a form of flattery, but at least they should link to our Cloud Agile partner page when they plagiarize like that. 

In contrast, EMC's announcement of FAST today only uses the word agile once, in Pat Gelsinger's quote:

“Over the past two years, EMC has optimized all of its major storage architectures to support new levels of automation required in virtual data center environments and for the transition to private clouds. These dynamic and agile environments require the capabilities that EMC’s FAST technology provides for effective management and scaling.  This is an area of significant investment for EMC and we are the only one offering this technology across high-end, mid-tier and unified platforms.”
- Pat Gelsinger, EMC President and Chief Operating Officer, Information Infrastructure Products

Online data movement is a big deal for storage and FAST puts it squarely in the mainstream of storage software. Gelsinger is right about virtual environments being dynamic and agile, but the problem with FAST is that the underlying storage does not measure up and FAST shines a spotlight on those shortcomings.  If you are going to have online data movement, you need to have the ability to make the results of those data movement operations productive - without turning your storage utilization goals upside down. FAST undoubtedly will work great where EMC storage is under-utilized and very expensive, but how will it work when you are trying to reduce the cost of storage by increasing storage utilization? 

It also looks like EMC is backing away slightly from their bullish position on SSDs. I was wondering how they were going to deal with their disappointing SSD sales when they finally announced FAST.

Speaking of bullish, I found this little video that I thought I'd share with you of some truly agile guys that really know their bull!

Symantec beats FAST out the door with SSD support in Dynamic Storage Tiering

While some have wondered whether or not EMC was going to be able to get their FAST product announced this year, others have been keeping their heads down getting work done.  For instance, Symantec, who today announced their Dynamic Storage Tiering feature for SSDs in their Storage Foundation products.

Of course, many probably wonder why the heck I'm writing about this seeing how 3PAR doesn't have support for SSDs in it's products yet.  That's easy. A v-Max with FAST is going to be more of a science project than a production system that actually gets work done.  I'm more concerned about customers buying somebody else's SSD-enabled array and using it with Symantec's Dynamic Storage Tiering than I am about FAST on v-Max.

But I'm not that concerned because the SSD market has been slow to develop - even by EMC, the company that has been leading the charge (and inventory buildup).  And even though they like to point to the check boxes in the feature checklist, big wide striping (the kind that flattens disk contention problems) with a v-Max is still an exercise in storage contortionism, unlike on a 3PAR, where its the default behavior.

But all this will change over time and the cost of deploying SSDs is going to come down as enabling software for SSDs becomes available and is refined. Even EMC's software will slowly get better. Despite the performance of the SSD devices - and EMC's wishes, the race for best of breed SSD functionality is going to be much more of a marathon than a sprint.

So where's 3PAR?  We've been shipping DO (Dynamic Optimization) for 4 years and today we announced the policy advisor for automating most of the tasks that used to take admins time to work through.  Changing service levels for volumes just got a lot easier. Drive speed, RAID levels, additional drives - if you want to change them, you can - and it doesn't take weeks or months and piles of spreadsheets to figure it out.