Primary data’s path to better data storage presented at SFD8

IMG_5606rz A couple of weeks ago we met with Primary Data, Lance Smith, CEO, David Flynn, CTO and Kaycee Lai, SVP Product & Sales who were presenting at Storage Field Day 8 (SFD8, videos of their sessions available here). Primary Data has just emerged out of stealth late last year and has ~$60M in funding. Also they have Steve Wozniak (of Apple fame) as Chief Scientist, but he wasn’t at the SFD8 session ūüôĀ

Primary Data seems out to change the world. At first I thought this was just another form of storage virtualization but they are laser focused on data virtualization or what they call data mobility. It differs from pure storage virtualization by being outside the data path.  (I have written about data virtualization before as well as the data hypervisor a long time ago). Nowadays they seem to be using the tag line of data in motion.

Why move data?

David has a theory behind the proliferation of startup storage companies. The spectrum behind capacity and performance has gotten immense, over time, which has provided an opening for a number of companies to address these widening needs.

David believes that caching at the storage system or in the servers is an attempt to address this issue by “loaning” the data from the storage silo to the cache. This is trying to supply a¬†lower cost $/IOP for the data. Similar considerations are apparent at the other side where customer’s use¬†archive or backup services to take advantage of much cheaper $/GB storage.

However, given the difficulty of moving data around in present day storage environments, customer data has become essentially immobile. Primary Data is trying to bring about a data mobility revolution and allow data to move over this spectrum of performance and capacity of storage with ease. Doing so easily, will provide significant benefits as customers can more fully take advantage of the various levels of performance and capacity in their data center storage environments.

Primary Data architecture

IMG_5607Primary Data is providing data mobility by using their meta-data service called the DataSphere appliance and their client software running on host servers called the Data Portal. Their offering can be best explained in three layers:

  • Data virtualization layer – provides continuity of identity and continuity of access across multiple physical storage systems. That is the same data (identity continuity) can be accessed wherever it resides (access continuity) by server applications. Such access and identity must transcend access protocols and interfaces. The Data Portal client software intercepts the server data activity and does control plane activity using¬†the DataSphere appliance and performs IO directly using the physical storage.
  • Objective based data management – supplies a data affinity service. That is data can have¬†a temporary location relationship with physical storage depending on the current performance (R:W, IOPS, bandwidth, latency) and protection (durability, availability, disaster recoverability, security, copy-ability, version-ability) characteristics of the data. These data objectives are matched to the capabilities or service catalog of the storage infrastructure and data objectives can change over time
  • Analytics in the loop – detects the performance and other characteristics of the storage and data in real-time. That is by monitoring the storage IO activity Primary Data can determine the actual performance attribute of the storage. Similarly, by monitoring the applications IO characteristics over time the system can determine the performance objectives of its data. The system also takes advantage of SMI-S to define some of the other characteristics of the storage systems.

How does Primary Data work?

Primary Data has taken advantage of parallel NFS extensions (pNFS) in NFSv4 to externalize and separate the storage control plane from the IO data plane. This works well for native Linux where the main developer of the Linux file system stack is on their payroll.IMG_5608rz

In Windows they put a filter driver in front of SMB to split off the control from data IO plane. Something similar is done for VMware ESX servers to supply the control-data plane split but in this case there is a software defined Data Portal that goes along with the DataSphere Service client that can do it all within the same ESX server. Another alternative exists and that is to use the Data Portal appliance as a storage virtualization service but then the IO data path goes through the portal.

According to their datasheet they currently support data virtualization services for NetApp cDOT and 7-mode, EMC Isilon OneFS7.2, and Nexenta 4.x&5.0 but plan on more.

They are not quite GA yet, but are close.

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What’s wrong with SPECsfs2008?

I have been analyzing SPECsfs results now for almost 7 years now and I feel that maybe it’s time for me to discuss some of the t problems with SPECsfs2008 today that should be fixed in the next SPECsfs20xx whenever that comes out.

CIFS/SMB

First and foremost, for CIFS SMB 1 is no longer pertinent to today’s data center. The world of Microsoft has moved on to SMB 2 mostly and are currently migrating to SMB 3. ¬†There were plenty of performance fixes in the last years SMB 3.0 release which would be useful to test with current storage systems. But I would be even be somewhat happy with SMB2 if that’s all I can hope for.

My friends at Microsoft would consider me remiss if I didn’t mention that since SMB 2 they no longer call it CIFS and have moved to SMB. SPECsfs should follow this trend. I have tried to use CIFS/SMB in my blog posts/dispatches as a step in this direction mainly because SPEC continues to use CIFS and Microsoft wants me to use SMB.

In my continuing quest to better compare different protocol performance I believe it would be useful to insure that the same file size distributions are used for both CIFS and NFS benchmarks. Although the current Users Guide discusses some file size information for NFS it is silent when it comes to CIFS. I have been assuming that they were the same because of lack of information but this would be worthy to have confirmed in documentation.

Finally for CIFS, it would be very useful if there could be a closer approximation of the same amount of data transfers that are done for NFS. ¬†This is a nit but when I compare CIFS to NFS storage system results there is a slight advantage to NFS because NFS’s workload definition doesn’t do as much reading as CIFS. In contrast, CIFS has slightly less file data write activity than the NFS benchmark workload. Having them be exactly the same would help in any (unsanctioned) comparisons.

NFSv3

As for NFSv3, although NFSv4 has been out for more than 3 years now, it has taken a long time to be widely adopted. However, these days there seems to be more client and storage support coming online every day and maybe this would be a good time to move on to NFSv4.

The current NFS workloads, while great for the normal file server activities, have not kept pace with much of how NFS is used today especially in virtualized environments. As far as I can tell under VMware NFS data stores don’t do a lot of meta-data operations and do an awful lot more data transfers than normal file servers do. Similar concerns apply to NFS used for Oracle or other databases. Unclear how one could incorporate a more data intensive workload mix into the standard SPECsfs NFS benchmark but it’s worthy of some thought. Perhaps we could create a SPECvms20xx benchmark that would test these types of more data intensive workloads.

For both NFSv3 and CIFs benchmarks

Both the NFSv3 and CIFS benchmarks typically report [throughput] ops/sec. These are a mix of all the meta-data activities and the data transfer activities.  However, I think many storage customers and users would like a finer view of system performance. .

I have often been asked just how many files a storage system actually support. This depends of course on the workload and file size distributions but SPECsfs already defines this. As a storage performance expert, I would also like to know how much data transfer can a storage system support in MB/sec read and written.  I believe both of these metrics can be extracted from the current benchmark programs with a little additional effort. Probably another half dozen metrics that would be useful maybe we could sit down and have an open discussion of what these might be.

Also the world has changed significantly over the last 6 years and SSD and flash has become much more prevalent. Some of your standard configuration tables could be better laid out to insure that readers understand just how much DRAM, flash, SSDs and disk drives are in a configuration.

Beyond file NAS

Going beyond SPECsfs there is a whole new class of storage, namely object storage where there are no benchmarks available. I would think now that Amazon S3 and Openstack Cinder are well defined and available that maybe a new set of SPECobj20xx benchmarks would be warranted. I believe with the adoption of software defined data centers, object storage may become the storage of choice over the next decade or so. If that’s the case then having some a benchmark to measure object storage performance would help in its adoption. Much like the original SPECsfs did for NFS.

Then there’s the whole realm of server SAN or (hyper-)converged storage which uses DAS inside a cluster of compute servers to support block and file services. Not sure exactly where this belongs but NFS is typically the first protocol of choice for these systems and having some sort of benchmark configuration that supports converged storage would help adoption of this new type of storage as well.

I think thats about it for now but there’s probably a whole bunch more that I am missing out here.

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