The above chart was from our July newsletter Exchange Solution Reviewed Program (ESRP) performance analysis for 1000 and under mailbox submissions. I have always liked response times as they seem to be mostly the result of tight engineering, coding and/or system architecture. Exchange response times represent a composite of how long it takes to do a database transaction (whether read, write or log write). Latencies are measured at the application (Jetstress) level.
On the chart we show the top 10 data base read response times for this class of storage. We assume that DB reads are a bit more important than writes or log activity but they are all probably important. As such, we also show the response times for DB writes and log writes but the ranking is based on DB reads alone.
In the chart above, I am struck by the variability in write and log write performance. Writes range anywhere from ~8.6 down to almost 1 msec. The extreme variability here begs a bunch of questions. My guess is the wide variability probably signals something about caching, whether it’s cache size, cache sophistication or drive destage effectiveness is hard to say.
Why EMC seems to dominate DB read latency in this class of storage is also interesting. EMC’s Celerra NX4, VNXe3100, CLARiiON CX4-120, CLARiiON AX4-5i, Iomega ix12-300 and VNXe3300 placed in the top 6 slots, respectively. They all had a handful of disks (4 to 8), mostly 600GB or larger and used iSCSI to access the storage. It’s possible that EMC has a great iSCSI stack, better NICs or just better IO scheduling. In any case, they have done well here at least with read database latencies. However, their write and log latency was not nearly as good.
We like ESRP because it simulates a real application that’s pervasive in the enterprise today, i.e., email. As such, it’s less subject to gaming, and typically shows a truer picture of multi-faceted storage performance.
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The complete ESRP performance report with more top 10 charts went out in SCI’s July newsletter. But a copy of the report will be posted on our dispatches page sometime next month (if all goes well). However, you can get the ESRP performance analysis now and subscribe to future free newsletters by just using the signup form above right.
For a more extensive discussion of current SAN block system storage performance covering SPC (Top 30) results as well as ESRP results with our new ChampionsChart™ for SAN storage systems, please see SCI’s SAN Storage Buying Guide available from our website.
As always, we welcome any suggestions or comments on how to improve our analysis of ESRP results or any of our other storage performance analyses.