What is a good strip size for Raid controllers

[rudder]

I have been trying to find this on HP's website. I was under the impression that using a 16K stripe size for a raid 1 volume would be more efficient that a 128K stripe size. HP defaults the stripe size to 128K. What are the benefits of using that larger stripe size?

 

[rudder]

I found a document that says 128K is default because it gives good performance based on a variety of applications. What would be the best stripe size for a web server versus application server ,database or file server?

 

[Matthias99]

There's no way to know without knowing more about what you're doing on the server.

Ideally, if your average I/O size is pretty small, you want each I/O to fit into a single disk stripe if possible (so that only one disk has to service each I/O, letting you exploit read parallelism as much as possible). For something like a web or database server, this means the optimum size could be as small as just a few kilobytes. Other types of applications could vary wildly, depending on what they are doing.

For something like a file server (where you expect to do lots of large sequential reads and/or writes), you would want the stripe size to be as large as possible. The controller has to break down your I/Os to fit into the stripes, and if you use a small stripe size, it has to break them down into more pieces (which adds overhead).

If you do not have a particular need or reason for changing it, leave it at the default. 64 or 128K is not a bad size, and will work fine for most applications (and is unlikely to cause anything to lose too much performance). Tuning it specifically for your apps can yield a few percent of performance gain -- or absolutely kill your disk performance.