On Wed, 2006-02-01 at 07:54 -0500, Sean Cook wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > They are all different questions: > > > > * Hardware RAID vs Software RAID > > Hardware RAID offers more performance and often more sophisticated RAID > > features. That is debatable :-) For really high-end systems hardware raid (3ware, SAN box, ...) is more performant, but even on a modestly loaded Athlon64 you'll (usually) be I/O limited before CPU limits become visible
> > Another advantage is that Hardware RAID controllers often offer you the > > opportunity to extend your RAID array beyond the usual 4 SATA > > interfaces. Depends on the card though. I'm running a software raid spanned over 3 controllers ... I'm not aware of a hardware-based solution that even comes close to that flexibility. > Back in the day... we were running the LSI MegaRAID controllers with > RAID 1 on 9gig SCSI disks, we were choking our application > (mysql/mod_perl) we took the MegaRAID controller out and performance > increased by about 25%. (note: this is a real world situation) Even if this is anecdotal - my experience is very similar. Software raid5 on an Athlon-1000 (basically a box of leftovers) takes ~7% CPU to saturate a 100Mbit line. An older 3ware controller maxed out at similar speeds, slightly lower CPU load - but adding more RAM and a slightly faster CPU is in this case much cheaper and faster than buying a new controller. Also changing controllers might not be possible without wiping and rebuilding the array. But if you need a disk array with maximum performance I'd still suggest a hardware-based solution. -- Stand still, and let the rest of the universe move
signature.asc
Description: This is a digitally signed message part
