Software RAID-5 block size?

[TeeJayHoward]

Software RAID-5
XFS filesystem
5x320GB SATA
Debian w/2.6 kernel

(Phrase "block size" used instead of "stripe size". If I'm misusing either phrase please inform me)

Data stored includes anime avi/mkv/ogm files (100-300MB each) and DVD ISOs (3.9-8GB each). Nothing else. From what I know of RAID, I want block sizes that most closely resemble the smallest file I'll open, right? I've never heard of a 100MB block, so... Uhm... Which block size should I use when I create the array? 256K? 512K? Or do I have it backwards? Should I be going for smaller block size?

And of the drives I'm using: Should I sell my existing two WD 320GB SE drives and pick up 5 WD 320GB RE drives? Or just buy three more WD 320GB SE's? Is the Raid Edition worthwhile for something as simplistic as this? Everything's going in my multipurpose main box (gaming rig, coding rig, enertainment center, file server, web server), which is always on, but rarely doing anything. (The array would only be in use for a few hours a day)

 

[unhappy_mage]

64k or whatever's the default should be fine - you're probably never hitting this stuff at more than 20 MB/s in either direction, so speed isn't really necessary. I would suggest getting the RE drives.

 

[TeeJayHoward]

Necessary? No... But I'd like to learn. And a little extra speed shouldn't hurt anything.

 

[Dew]

I'm not sure how applicable this is to your software RAID-5, but check this out:
http://www.highpoint-tech.com/PDF/rr2320/RocketRAID 2320 Boosting Real World Applications.pdf