RAID 5 striping size

[parallon]

Can anyone tell me the benefits of setting up striping for RAID 5 as low as 2kb or as high as 128kb? I am a little new to this stuff, and we are getting ready to install a new server, and I noticed this in the DELL manual. Also, I read that they recommend a 200MB DOS partition, 8GB max for the system partition, and the rest is available to work with. Can anyone see any benefits of creating multiple logical partitions as opposed to just sorting through folders. I know these questions may seem a little elementary, but you have to start somewhere. Thank you in advance for your time.

Parallon "I used to think that the more that you knew, the farther you would go, then I realized that the more that you know, the more they use you."

-Me

 

[Morsing]

Normally it should be between 4kb and 16kb. 128kb is a bit extreme.
It depends on what you want to do really but if it's not a speciealised box just leave it at eight. Don't know exactly what impact it would have to set it very high.

Regarding seperat partitions:
It's a big advantage for reinstalling a system that you can leave all the non-system stuff alone.

Cheers Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support

 

[Bing59]

With striping it is best to use the size that the applications can best utilize. If the file sizes are 16k and you have a block size of 64K, then each time a file is written a 64K block on the disk will be used.
Block size and file sizes also come into play when stripping across disks. If a disk uses 64K blocks then only a file larger than this can be striped across multiple disks.
Example of a read or write bolck size of 16K and a file of 40K, on a three drive raid5 set all three drives would particpate in the operation. 16k + 16K + 8K

Hope that helps.
Bing

 

[parallon]

Bing-59. Thanks for the info. Now the question changes to "is it possible to change to a smaller size if you feel that you have made it too big?" The default was 64k, and wouldn't you know it, that is where I left it. Is it too late? It is a hardware RAID 5 setup.

Thanks,

Parallon "I used to think that the more that you knew, the farther you would go, then I realized that the more that you know, the more they use you."

-Me