December 18, 2009 at 12:46 pm
Anyone have any experience with the new IBM XIV storage platform particularly relating to performance with SQL Server? Things look good on paper, but I'm looking to hear some thoughts from those that may already be using it or plan on implementing it.
December 18, 2009 at 7:51 pm
I haven't used it nor do I plan to anywhere in the near future, but just reading the descriptions, its typical of most SAN's, touting self tuning configuration and really large disks to increase storage capacity for lower TCO's. Some things that would concern me are:
... based on a grid of standard, off-the-shelf hardware components connected in any-to-any topology by means of massively paralleled, non-blocking Gigabit Ethernet.
...leveraging the capacity and cost benefits of Very High Density Slower Rotation (VHDSR) drives
Neither of these is ideal for SQL Server. SQL is unlike any other line of business disk consumer. You want really large IOPS numbers and you get that by having lots of fast, small capacity drives in 1+0 RAID arrays. Most SAN's like this one don't get configured in a 1+0 configuration because it costs twice as much for the same storage amount, and they generally have large capacity drives, 300GB-1TB each, optimized for capacity and not IOPS necessarily.
The whole self-tuning to reduce hot-spots sounds great on paper, but I have yet to see it be good for SQL Server, or when SAN utilization is at or near capacity because there is nowhere to move the load to eliminate the hotspot.
For personal experience with another enterprise SAN configured for capacity and used for Oracle and SQL, your results will be very disappointing. I've used a SAN with 300GB drives in RAID 6 configurations and the resulting performance is worse through the SAN than for a 6 disk RAID 5 locally using 146GB 15K drives.
If you properly configure the SAN it could work just fine. I'd ask the vendor for SQLIO numbers from the SAN. SQLIO is a tried and true method of stress testing a disk array to get the possible performance characteristics related to a SQL Server based workload. You want to see 64K Random Read and Write and 64K Sequential Read and Write numbers from the SAN. If it is going to be shared by other components of the enterprise, you want to also try and get numbers under nominal load so you aren't getting artificial numbers that aren't realistic to your expected total workload.
That's a tough order, but its how you'd know what the SAN can or can't do. You also want to have a resource from the vendor that understands SQL Server workloads when the SAN is setup and configured on site. Most SAN admins and consultants don't setup the SAN properly for SQL resulting in bad performance characteristics.
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December 21, 2009 at 7:42 am
Thanks Johnathan. Your points mirror many of my concerns from reading about SQL server and SAN implementations. They also want to put pretty much everything requiring storage inside our enterprise on this solution. Exchange, VMs, etc. Raises a real red flag with myself as a DBA, but would make the Sys admin job much easier (theoretically).
Unfortunately, I'm a rather junior member here and the Sys Admins have a lot more pull when it comes to this decision. I will continue to read up. Your feedback was much appreciated. Thank you.
December 21, 2009 at 8:15 am
Jr or Sr, if you are responsible for SQL, this should be a concern that you raise, and be loud about it. Document the concern in an email to the system admins and copy your management. That way in a year when you face IO bottlenecks in SQL, you can show that you raised the concern. It may be that your SQL Server IO requirements are low enough that it won't be a problem. Another option would be to request the option to bring in a Microsoft Engineer for a consult or open a support case with Microsoft to review the configuration and requirements.
Jonathan Kehayias | Principal Consultant | MCM: SQL Server 2008
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Troubleshooting SQL Server: A Guide for Accidental DBAs[/url]
January 22, 2010 at 5:50 am
December 22, 2011 at 5:34 am
My experiences with XIV have been mixed, FWIW.
We currently have a 5TB ODS on XIV Gen 2, with a 5TB datamart soon to come online.
Tech Services staff love it, as it's a black box completely managed by IBM staff.
The raw IOPs are great, but the decision was made to throttle ODS throughput to 400MB/s by Tech Services, due to them not wanting the user base maxing out the server during queries (!). Our development HP DL380 + 3x P2000 can top 700MB/s.
You need to redesign your SSIS packages to get the performance increase XIV fans tell you of; you'll hit the buffer limits within SSIS before XIV squeals, but we've had to set MAXDOP to 8 on a 4 x 8 core server set up to get decentish performance and XIV would prefer it to be set to 1.
We've had cluster resource deadlocks during the ETL on the TempDB volume and the Logs volume. These are effectively LUNS striped across every single disk in the XIV array. The SSIS package hung, the memory maxed out (why, we're not entirely sure) and eventually the cluster failed over whilst the node BSODd.
It's not my favourite storage solution, but we're stuck with it. IBM staff don't seem to be interested in anything other than getting SQL Server to do things the XIV way, there's no indication that they're working with MS to integrate, either.
November 22, 2013 at 10:03 am
Hi I wanted to revive this thread to see if anyone has used XIV? Their experiences with it. IBM is now on the "third release" of their Storage Product for XIV - Gen3.
http://www.storageperformance.org/results/benchmark_results_spc1
There's a posting for XIV.
I tried to search the net for some forum posts, although i haven't visited storage sites or posted a question directly myself anywhere... this is my first time..... Thought I'd first try here since there was a posting I saw at one time.
As with all companies marketing is great - but to get optimum performance wondering if it requires some expert skill sets in storage especially IBM storage design, however it seems the whole idea of XIV is to make it easier that if you're short on staff and don't have the time for that high specialization it would help an organization.
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