Useful RAID Tools?

msaes asks: "I've got 4 machines now that I'm running RAID5 on. 3 are Dell's with the PERC (Adaptec) SCSI RAID controller, and one is a software (Win2k Pro) RAID. In all 4 cases, the MS defrag program, and the Norton Speedisk program said that the logical drives are horribly fragged. And from disk I/O performance, I'd tend to agree. Running the MS defrag on any of them is futile. It just cranks away for a while and then cheerfully says that it's done, with little or no improvement. I've run Speedisk on the software RAID machine and it's run for about 3 days solid now and performance on the drive is only getting worse. My question is: Does de-fragmentation software get confused by RAID volumes and actually fragment the drive worse?" Which brings yet another question. What tools are out there for the effective management of RAID volumes? Other partition types have a wide variety of maintenance tools, aside from the defrag utility, like a partition editor, an undelete tool, analyzers, and so on. What about RAID? What tools do you use to make sure your RAID volumes are happy and healthy?

Comments

Wierd

[itwerx]

Sounds like you have something else going on unrelated to RAID. Hardware RAID is completely transparent and shouldn't affect your defragging, (which, by the way, is still effective because the controller still accesses the drives in a consistent manner).
I would look at what's running on the system (virus?) or maybe the driver for the RAID card(s).
BTW DiskKeeper is pretty good...

er..

[Wakko Warner]

If you've got a Dell with PERC controllers, they come with great PERC utilities that will do everything you need. Install them. It's a good idea to be able to monitor your RAID 5 sets.

- A.P.

Questions

[sharkey]

What software are you using to create a software RAID-5 on your Win2000 Pro PC, since the Pro version cannot create RAID arrays on its own. Perhaps you should talk to the vendor about fragmentation, and defrag software issues. The PCs with an actual RAID controller are different. Windows, and thus Diskeeper (the MS defrag program), sees them as nothing but a single disk. I have had no problems defragging hardware or software RAID arrays (1 & 5) using Diskeeper.

Performance-wise, it goes into the toilet while defragging. The defrag operation moves fragmented files to free disk space, then copies them back to the "beginning" of the drive to put the file fragments into adjacent clusters, thus making them contiguous. This chews up a huge amount of disk I/O, stretches out seek times, etc. Also, how much free space do you have on these volumes? The less free space you have, the less space the defrag program has to work with. On a volume that is almost full, defragmentation can take a LONG time, and you will likely need several passes to see significant improvement. If you can, move some of the files off to another volume or tape/DVD/etc., defrag, then move them back. If you get the retail version of Diskeeper, it can consolidate directories at boottime, allowing a bit more optimization.

And remember, this is SCSI you're dealing with. Never underestimate the power of a well-sacrificed chicken.