I have a guy who wants me to move his databases to an external drive. Hardware is my major weakness and I usually think I am McGyver when I can swap out a RAM board in my home PC. Whenever guys in the office start talking hardware, I go hide in the bathroom.
I know I have read that this is a very bad idea in some book and a few message board threads. This guy is going to use SCSI and it is going to be attached to the same controller as his other disks. I know he should have a battery backup for the drive especially if it employs write caching and that it should be formatted to NTFS and not FAT32.
I googled\technetted\BOLed\MSDNed this for 2 hours yesterday because I remember reading something about disc controllers and external drives and SQL Server being a recipe for disaster but I could not find anything to back me up.
Any words of wisdom or advice?Sean,
Well, it sounds like he is going to use a external drive array attached to his existing hardware.
If that's the case, then I wouldn't get too worried...with the following exceptions.
- Make sure that it is a external array device of some kind. Something that they can have HotSwap drives. Something like HP's Modular Smart Array Storage Systems(I'll let you Google for a picts/desc...MSA30 or MSA20). Home brewed equipment may not be the best choice.
- UPS the external drive array. Using the existing UPS or not can be a touchy subject. My suggestion would be to get a second UPS if the budget will allow it.
- If the budget will allow it, get a second drive card for the external array. Spend the money on a top end SCSI controler card. On-Board battery backup, monster cache, etc.
Most/All clustered SQL servers use a external drive array attached to the cluster nodes by a SCSI cable. Got one running now with no issues. Prior SQL server also used a external array and did not have any issues.
My company runs Novell servers with external arrays. From a HW standpoint it is a solid performer.
If they need it, with the external array they would have the ability to create multiple RAID arrays and seperate the data from the log files which could give them some performance benifits.
From an operational standpoint, when they use the external array with the server the powerup/powerdown sequence is important.
Powerdown the server first, then the external device. Sounds simple, but people sometimes forget and this is the easyest way to data corruption and loss.
When they powerup, powerup the external devise first and let the drives spin to speed prior to powering up the server. Powering up both at the same time is not recommended basically because I was always told not to do it that way and it sounds reasonable to me.
About all I can think of off the top of my head....
bEH|||thank you.
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