Screaming IOP performance with StarWind’s new NVMeoF software & Optane SSDs

Was at SFD17 last week in San Jose and we heard from StarWind SAN (@starwindsan) and their latest NVMeoF storage system that they have been working on. Videos of their presentation are available here. Starwind is this amazing company from the Ukraine that have been developing software defined storage.

They have developed their own NVMe SPDK for Windows Server. Intel doesn’t currently offer SPDK for Windows today, so they developed their own. They also developed their own initiator (CentOS Linux) for NVMeoF. The target system was a multicore server running Windows Server with a single Optane SSD that they used to test their software.

Extreme IOP performance consumes cores

During their development activity they tested various configurations. At the start of their development they used a Windows Server with their NVMeoF target device driver. With this configuration and on a bare metal server, they found that they could max out the Optane SSD at 550K 4K random write IOPs at 0.6msec to a single Optane drive.

When they moved this code directly to run under a Hyper-V environment, they were able to come close to this performance at 518K 4K write IOPS at 0.6msec. However, this level of IO activity pegged 100% of 8 cores on their 40 core server.

More IOPs/core performance in user mode

Next they decided to optimize their driver code and move as much as possible into user space and out of kernel space, They continued to use Hyper-V. With this level off code, they were able to achieve the same performance as bare metal or ~551K 4K random write IOP performance at the 0.6msec RT and 2.26 GB/sec level. However, they were now able to perform only pegging 2 cores. They expect to release this initiator and target software in mid October 2018!

They converted this functionality to run under ESX/VMware and were able to see much the same 2 cores pegged, ~551K 4K random write IOPS at 0.6msec RT and 2.26 GB/sec. They will have the ESXi version of their target driver code available sometime later this year.

Their initiator was running CentOS on another server. When they decided to test how far they could push their initiator, they were able to drive 4 Optane SSDs at up to ~1.9M 4K random write IOP performance.

At SFD17, I asked what they could have done at 100 usec RT and Max said about 450K IOPs. This is still surprisingly good performance. With 4 Optane SSDs and consuming ~8 cores, you could achieve 1.8M IOPS and ~7.4GB/sec. Doubling the Optane SSDs one could achieve ~3.6M IOPS, with sufficient initiators and target cores with ~14.8GB/sec.

Optane based super computer?

ORNL Summit super computer, the current number one supercomputer in the world, has a sustained throughput of 2.5 TB/sec over 18.7K server nodes. You could do much the same with 337 CentOS initiator nodes, 337 Windows server nodes and ~1350 Optane SSDs.

This would assumes that Starwind’s initiator and target NVMeoF systems can scale but they’ve already shown they can do 1.8M IOPS across 4 Optane SSDs on a single initiator server. Aand I assume a single target server with 4 Optane SSDs and at least 8 cores to service the IO. Multiplying this by 4 or 400 shouldn’t be much of a concern except for the increasing networking bandwidth.

Of course, with Starwind’s Virtual SAN, there’s no data management, no data protection and probably very little in the way of logical volume management. And the ORNL Summit supercomputer is accessing data as files in a massive file system. The StarWind Virtual SAN is a block device.

But if I wanted to rule the supercomputing world, in a somewhat smallish data center, I might be tempted to put together 400 of StarWind NVMeoF target storage nodes with 4 Optane SSDs each. And convert their initiator code to work on IBM Spectrum Scale nodes and let her rip.

Comments?

One platform to rule them all – Compellent&EqualLogic&Exanet from Dell

Compellent drive enclosure (c) 2010 Compellent (from Compellent.com)
Compellent drive enclosure (c) 2010 Compellent (from Compellent.com)

Dell and Compellent may be a great match because Compellent uses commodity hardware combined with specialized software to create their storage subsystem. If there’s any company out there that can take advantage of commodity hardware it’s probably Dell. (Of course Commodity hardware always loses in the end, but that’s another story).

Similarly, Dell’s EqualLogic iSCSI storage system uses commodity hardware to provide its iSCSI storage services.  It doesn’t take a big leap of imagination to have one storage system that combines the functionality of EqualLogic’s iSCSI and Compellent’s FC storage capabilities.  Of course there are others already doing this including Compellent themselves which have their own iSCSI support already built into their FC storage system.

Which way to integrate?

Does EqualLogic survive such a merger?  I think so.  It’s easy to imagine that Equal Logic may have the bigger market share today. If that’s so, the right thing might be  to merge Compellent FC functionality into EqualLogic.  If Compellent has the larger market, the correct approach is the opposite. The answer lies probably with a little of both.  It seems easiest to add iSCSI functionality to a FC storage system than the converse but the FC to iSCSI approach may be the optimum path for Dell, because of the popularity of their EqualLogic storage.

What about NAS?

The only thing missing from this storage system is NAS.  Of course the Compellent storage offers a NAS option through the use of a separate Windows Storage Server (WSS) front end.  Dell’s EqualLogic does the much the same to offer NAS protocols for their iSCSI system.  Neither of these are bad solutions but they are not a fully integrated NAS offering such as available from NetApp and others.

However, there is a little discussed part, the Dell-Exanet acquisition which happened earlier this year. Perhaps the right approach is to integrate Exanet with Compellent first and target this at the high end enterprise/HPC market place, keeping Equal Logic at the SMB end of the marketplace.  It’s been a while since I have heard about Exanet, and nothing since the acquisition earlier this year.  Does it make sense to backend a clustered NAS solution with FC storage – probably.

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Much of this seems doable to me, but it all depends on taking the right moves once the purchase is closed.   But if I look at where Dell is weakest (baring their OEM agreement with EMC), it’s in the highend storage space.  Compellent probably didn’t have much of a foot print there as possible due to their limited distribution and support channel.  A Dell acquisition could easily eliminate these problems and open up this space without having to do much other than start to marketing, selling and supporting Compellent.

In the end, a storage solution supporting clustered NAS, FC, and iSCSI that combined functionality equivalent to Exanet, Compellent and EqualLogic based on commodity hardware (ouch!) could make a formidable competitor to what’s out there today if done properly. Whether Dell could actually pull this off and in a timely manner even if they purchase Compellent, is another question.

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