CNC - Migrating The Database from DAS to SAN

Howdy,

I was wondering if any of you out there have converted your Production Database Server files from Direct Attached Storage to residing on a Storage Area Network.

Using a hardware clone of our production database server, we have done a large battery of tests on the system using the SAN, including interactive user applications, batch jobs, re-indexing, etc. -- It appears that the SAN will be able to support our live production system.

I'm looking for any feedback on any known caveats, or thoughts on if there is any decent way to do a final volume testing of the database system in this regard. All other servers (Application, Deployment, etc.) will not be changing at this time.

Thanks in Advance,

Hi John

I think we've talked about this in the past ! Glad to see that you're moving towards a SAN environment.

Here are some of the caveats I've spoken about in the past. Make sure that your production database is on a RAID10 configuration. The more arms the better. Although there are low-cost SAN solutions out there at the moment, remember that JDE will absolutely generate the highest I/O per second, and will therefore need the lowest latency possible.

Try to pin your archive logs/log files into memory. These are exceptionally high I/O files - and everything "queues" behind these requests - pinning them either into memory OR using a SSD device will absolutely pay off.

If you are looking at utilizing iSCSI - then make sure that your network is dedicated. Preferably set up for 10Gb as opposed to Gigabit - and make sure that there are as few hops as possible between the database server(s) and the storage array.

iSCSI is now starting to come into its own. There are some very low cost alternatives to direct attached storage these days - and if architected correctly, can provide incredible performance.

John,

Go for it. We are on our third generation of SANs. Follow Jon's advice of Raid 1+0 and get as fast of a SAN as you can afford. In our shop, JDE was the first system to go on a SAN, now 90% of our servers use the SAN. Much more efficient use of disk space.

- Gregg

Thanks Gregg and Jon for the responses.

And yes Jon, I think we spoke of this back when you helped us with our Citrix / System volume testing.

Which is a great segue to a followup question:

Have either of you performed any kind of volume-test validation for your SAN? I currently have subjective time trials using OneWorld applications, and my objective Performance Monitor counters show the SAN peformance to be within the same range as my live DAS. Are these good metrics, or should I be doing something else as well?

If you have a decently tuned SAN, your performance should be substantially improved over local disks. As a non scientific performance measure, my full package build times have dropped from seven hours to 90 minutes due to newer hardware and suped up SANs.

A few things to look for:

more spindles are better than bigger hard drives.

A raid 1 + 0 configuration is ideal. http://en.wikipedia.org/wiki/RAID

There are various tiers of SANs. We have a Hitachi SAN right now with three tiers of storage. JDE is on Tier one. Outrageously fast, redundant, replicated drives.

User data is on tier 3, that is iSCSI non redundant drives that are backed up by a tape storage robot.

There is a definate science to tuning a SAN, but once you figure it out, you will see a nice boost in performance.

- Gregg

see This post -> #154121