The “Everything VMware at EMC” community is one of the most busy locations on ECN (the EMC Community Network), which I think is awesome :-)
The plea I made for customers to share their performance data (here) has now been viewed more than 1700 times!
I’m happy to announce three things:
1) We have our 30 winners! I love that they cross the globe, come in small/medium/large, and represent such a multi-vendor cross-segment of the community. I’m out of IX2s for now, so will be closing that down. If you want to continue to contribute – please go ahead, but I won’t be able to send more IX2s. All the folks listed below will be contacted for shipping info, and should receive your IX2’s shortly. Feedback on how you end up using them would be welcome!
- Not using EMC Storage: @MillardJK (VMFS/Eql); @chrisaug (NFS/NetApp); @arobinson (VMFS/aberdeen); @DefinIT (VMFS/SAS); @Aciske (VMFS, HP EVA); @dhainich (Both, Netgear and HP EVA4400); @dpironet (VMFS, HP MSA); @dvandooren2011 (VMFS, EqualLogic); @misteriks (VMFS, EqualLogic); @IanTech (VMFS, HP P4500); @Simon Andersen (VMFS, Dell MD3000i and Starwind); @jmarlhioud (VMFS, Starwind and HP P4000); @Otto-D (VMFS, IBM DS8700); @8P1r3tv (Both, IBM and NetApp); @Crowey (VMFS, SUN 6540); @jpaul_sms (VMFS, HP MSA); @BEIsass_SMS (VMFS, iSCSI SAS array); @mwpreston (VMFS, HP EVA 6400, MSA1000)
- Using some EMC storage: @Fox_inti *(NFS/EMC NS-960); @ryanb (Both/NetApp/EMC CX700); @Mrymom (VMFS/EMC CX4/CX3); @HerseyC * (Both NS-20, NFS home-brew); @jasonboche *(Both, ENC NS-120 and NetApp); @Fredric Jacquet (VMFS, CX3-80); @Iandog (Both, NS-120); @gwblok (VMFS, EMC CX4-240); @MTW (VMFS, EMC VMAX and HP EVA 4100); @benwaynet (VMFS, EMC CX3-40); @bweichman1 (VMFS, EMC AX4-5i); @elel12345 (VMFS, EMC DMX4, CX700)
2) Based on the data, and on other information sources we have our first VMware-centric IO stack optimization ready, and are looking for people to test it!
- If you’re an EMC customer using an EMC Celerra, EMC Unifed NS series, or EMC VNX array and using NFS datastores, we have something we would like you to try. It’s experimental – so DO NOT DO THIS on a production array.
3) So, I’m opening a NEW thread, and NEW contest… Customers, EMCers, EMC Partners using any of the systems in topic #2 (@Fox_inti, @jasonboche, @HerseyC, @landog – you folks apply!!!), if you provide the “before and after” data (using the same process as in the original contest) to this thread on Everything VMware at EMC, I will send the first 30 to post an iPad (16GB Wifi version). For details – read below!
The EMC NFS performance through EMC NAS stack (which is used in differing ways) has always been very, very good for traditional NFS/CIFS (read: unstructured file, read biased) use cases. This set of recent face-melting SPEC SFS benchmarks shows how that lead has broadened with VNX (which can scale to leverage large amounts of SSD as both a cache and a tier). We were not kidding when we said 2011 was going to be a year of breaking records.
BUT – all is not rosy
DART’s IO path for transactional (read: skewed towards smaller block, more write intensive) has never had the same degree of optimization efforts as it is not a general purpose NAS profile. Over-simplifying, this mostly due to serialization of IOs through the NAS stack, and missed optimizations around this type of workload. To date, all the optimizations (uncached mode as an example) done automatically by the EMC vCenter plugin (VSI) have an effect, but don’t change how the NAS stack itself handles the IO path. This doesn’t mean that transactional workloads on EMC NAS is a BAD choice (many customers are using it and loving it), but rather that we hadn’t been optimizing as much as we could have. The two use cases where this effect is the strongest are Oracle on NFS and VMware NFS datastores.
The good news: Engineering optimization around BOTH the Isilon and DART NAS stacks has a lot coming around optimizing around these sorts of transactional NFS workloads – both in the near, and longer terms.
Some of the near-term DART optimizations (there are really big ones planned for the longer term) are ready for some early experimental engineering feedback. To understand better:
- The optimization is for the NAS write path – it has shown very large latency performance improvements in some test with very small IO random IO workloads on NFS datastores.
- Multi-VMs is important if you want to provide data. We know it's good with a single VM (4x better latency), but the way it's better is by reducing the serialization of writes through the NAS stack to the backend disk devices (which produces a lot less latency). The main questions are: a) how much it holds up with random, multi-vm workloads; b) whether performance regressed with other workloads (large IO sequential guest workloads)
- It is experimental. This means: Don’t use it in production – PERIOD. If you have a non-production Celerra/VNX use case, give it a shot. We’ve been playing with it for a while, so it seems solid, but never use non-production code in production environments.
So – how do you get it?
- For customers who would like to try the optimization, here is the process (this is the preferred process, as it formalizes feeback):
- the epatch is available to the tech support group, which is the usual method in which we release code.
- The epatch is called 184.108.40.2065 If your customer wishes to obtain and test with it, please open an SR with your local service representative and have them work with tech support to get the 220.127.116.115 e-patch so that you can schedule your upgrades.
- Please provide any feedback based on the experience that results from this patch. Negative or positive, we'd like to hear it.
- For non-customers (EMC Partners/employees) who would like to try the fix, the experimental DART epatch is here, with the MD5 here, and the release notes here.
What tests are the most interesting? Well – read here for the contest details. I’m thankful for any/all data.
Regardless, please provide any feedback you find. In particular, performance tests before/after with VM guest level small block, random workloads (with ranges of VMs in datastores) would be VERY appreciated.
Thanks, and as always – courteous comments welcome.