In our quarterly study on Exchange Solution Reviewed Program (ESRP) results we show a number of charts to get a good picture of storage subsystem performance under Exchange workloads. The two that are of interest to most data centers are both the normalized and un-normalized database transfer (DB xfer) charts. The problem with un-normalized DB xfer charts is that the subsystem supporting the largest mailbox count normally shows up best, and the rest of the results are highly correlated to mailbox count. In contrast, the normalized view of DB xfers tends to discount high mailbox counts and shows a more even handed view of performance.
We show above a normalized view of ESRP results for the category that were available last month. A couple of caveats are warranted here:
Normalized results don’t necessarily scale – results shown in the chart range from 5,400 mailboxes (#1) to 100,000 mailboxes (#6). While normalization should allow one to see what a storage subsystem could do for any mailbox count. It is highly unlikely that one would configure the HDS AMS2100 to support 100,000 mailboxes and it is equally unlikely that one would configure the HDS USP-V to support 5,400 mailboxes.
The higher count mailbox results tend to cluster when normalized – With over 20,000 mailboxes, one can no longer just use one big Exchange server and given the multiple servers driving the single storage subsystem, results tend to shrink when normalized. So one should probably compare like mailbox counts rather than just depend on normalization to iron out the mailbox count differences.
There are a number of storage vendors in this Top 10. There are no standouts here, the midrange systems from HDS, HP, and IBM seem to hold down the top 5 and the high end subsystems from EMC, HDS, and 3PAR seem to own the bottom 5 slots.
However, Pillar is fairly unusual in that their 8.5Kmbx result came in at #4 and their 12.8Kmbx result came in at #8. In contrast, the un-normalized results for this chart appear exactly the same. Which brings up yet another caveat, when running two benchmarks with the same system, normalization may show a difference where none exists.
The full report on the latest ESRP results will be up on our website later this month but if you want to get this information earlier and receive your own copy of our newsletter – just subscribe by emailing us.
As described more fully in last months SCI’s newsletter, to the left is a chart depicting Exchange Solution Reporting Program (ESRP) results for up to 1000 mailboxes in the database read and write per second category. This top 10 chart is dominated by HP’s new MSA 2000fc G2 product.
Microsoft will tell you that ESRP is not to be used to compare one storage vendor against another but more as a proof of concept to show how some storage can support a given email workload. The nice thing about ESRP, from my perspective, is that it represents a realistic storage workload rather than the more synthetic workloads offered by the other benchmarks.
What does over 3000 Exchange database operations per second mean to the normal IT shop or email user. It should mean more emails per hour can be sent/received with less hardware. It should mean a higher capacity to service email clients. It should mean a happier IT staff.
But does it mean happier end-users?
I would show my other chart from this latest dispatch that has read latency on it but that would be two charts. Anyways, what the top 10 Read Latency chart would show is that EMC CLARiiON dominates with the overall lowest latency and has the top 9 positions with various versions of CLARiiON and replication alternatives being reported in ESRP results. The 9-CLARiiON subsystems had a latency at around 8-11 msecs. The one CLARiiON on the chart above (CX3-20, #7 in the top 10) had a read latency around 9 msec. and write latency at 5 msec. In contrast, the HP MSA had a read latency of 16 msecs with a write latency of 5 msec. – very interesting.
What this says is that database transfers per second are now more like throughput measures and even though a single database operation (latency) may be almost ~2X longer (9 vs. 16 msecs), it can still perform more database transfer operations per second due to concurrency. Almost makes sense.
Are vendors different?
This probably says something more about the focus of the two storage vendor engineering groups – EMC CLARiiON on getting data to you the fastest and HP MSA on getting the most data through the system. It might also speak to what the vendor’se ESRP teams were trying to show as well. In any case, EMC’s CLARiiON and HP’s MSA have very different performance profiles.
Which vendor’s storage product makes best sense for your Exchange servers – that’s a more significant question?
The full report will be up on my website later this week but if you want to get this information earlier and receive your own copy of our newsletter – just subscribe by emailing us.