Date: Sun, 25 Mar 2001 10:41:28 -0500 From: Bill Moran <wmoran@iowna.com> To: Tim Joseph <tim@weeble.org.uk> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Simple SCSI/RAID on FBSD 4.x Message-ID: <3ABE11A8.FE5A0251@iowna.com> References: <Pine.BSF.4.33.0103251148440.69306-100000@doubtful.weeble.foo.uk>
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Tim Joseph wrote: > 1. Will software RAID 0 noticeably improve disk performance, even if all > of the disks are connected to the same controller? Is there a tailing off > of performance once you're past 2 or 3 disks on the same controller? Yes, as long as you're not saturating the controller. For example, if your controller can handle a total of 40 MB/s and each HDD can actually transfer a sustained 40MB/s, you're not going to see much improvement in speed with RAID (in theory) However, if you're controller can handle 160mb/s and each drive can transfer a sustained 40mb/s, in theory you'd benefit from 4 drives in RAID 0 config. > 2. Will a hardware RAID controller be worth it for just RAID 0? Probably, with hardware RAID you often get the option of hot swap, which is nice as well. Also, hardware RAID doesn't tie up your processor to do it's work. With modern fast processors, that probably isn't a very big issue, but if you want the ultimate in performance, hardware RAID is the way to go. > 3. Which "width" of SCSI gives the best bang for buck performance? I don't have prices, but the best bang I've seen so far is the SCSI-160 controllers with compatable drives, these things are FAST! > 5. Can I RAID a couple of hardrives, and have a separate CDRW/DVD unit on > the same controller? If you're using vinum, yes. If you've got a HW RAID controller, it will depend on the controller model's capabilities. > 6. Any recommendations for SCSI controllers, RAID controllers and/or SCSI > disks? They're a little pricy, but if you want performance, I recommend Adaptec 160 with IBM 160 drives. -Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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