RAID stripe sizes

[gherald]

Most opinions I've come across on this subject have been completely subjective. Is anyone here versed in the technical merits of various sizes?

Target is a general purpose WinXP PC that is used for EVERYTHING... gaming, browsing, office work, media, file serving, etc.

 

[Matthias99]

On a RAID controller, if you do a read/write request that's bigger than a single stripe, it has to be internally split into multiple reads/writes by the controller. So, for systems doing many small writes, you want as many writes as possible to fit into a single stripe (so that each write can be serviced by a single disk), but if the stripes are too large, you'll have problems with multiple reads/writes going to the same stripes simultaneously (which bogs things down considerably). So if you know (for example) that you're running a database server that reads and writes 4K pieces of data to disk all day long, you'd probably want a 4K or 8K stripe size.

For systems doing many large reads/writes (a video editing workstation, for instance), you want the stripes as large as possible, so there is less overhead in the RAID controller (the large reads/writes will get split fewer times with a larger stripe size).

Unless you're tuning the array for a specific application, just leave it at the default (probably 16KB or so). Feel free to play around with it, but I doubt you'll see much improvement for 'general' usage.

 

[MadAd]

I use 16k, seems to be good for general use - theres some tests using different stripe sizes here

http://www.adriansrojakpot.com/Speed_Demonz/IDE_RAID/RAID_01.htm

 

[gherald]

Thanks for the link... boy was I wrong in choosing a 64k stripe. I wanted something 'average', but it looks like it performs abysmally poor.

I'm about do for a reinstall anyway, 16k ought to work much better.

 

[Monoman]

shuttleteam (hopefully )will back me on this, the normal defualt is 64k stripe size. that will work fine for every normal non specialized user. 16k is still on the speciliazed size IMO...

 

[dkozloski]

My experience with SCSI raid is that disk stripe size makes very little difference but if you have a caching controller the cache stripe size makes a huge difference. For my work 64k seems about right for the cache stripe.