Date: Thu, 16 Dec 2004 20:02:06 +1100 From: Peter Jeremy <PeterJeremy@optushome.com.au> To: Gianluca <gianluca@gmail.com> Cc: asym <asym@rfnj.org> Subject: Re: drive failure during rebuild causes page fault Message-ID: <20041216090206.GC91817@cirb503493.alcatel.com.au> In-Reply-To: <6.1.2.0.2.20041215190056.02f9bfb8@mail.rfnj.org> References: <20041213052628.GB78120@meer.net> <6.1.2.0.2.20041215190056.02f9bfb8@mail.rfnj.org>
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On Wed, 2004-Dec-15 19:16:59 -0500, asym wrote: [audio jukebox] >>what would be your recommendations for this particular (and very limited) >>application? > >Honestly I'd probably go for a RAID1+0 setup. It wastes half the space in >total for mirroring, but it has none of the performance penalties of >RAID-5, If you're just talking about audio, then RAID-5 would seem a better choice. You get much higher effective space utilisation (75-90% rather than 50%) and even the degraded bandwidth is plenty for serving a couple of audio streams. > and upto half the drives in the array can fail without anything but >speed being degraded. Normally, you replace a drive soon after it fails. The risks of a second drive failing should be fairly low. Note that you should try to get drives from different batches - all vendors have the occasional bad batch and you don't want all your drives to die at once. >RAID5 sacrifices write speed and redundancy for the sake of space. Since >you're using IDE and the drives are pretty cheap, I don't see the need for >such a sacrifice. For Gianluca's application, write speed wouldn't seem to be an issue. Redundancy may or may not be an issue - it depends how quickly a failed drive can be replaced and whether the risk of one of the other drives failing during this period is acceptable. The main advantage of RAID-5 is increased space - and this would seem to be an important issue. -- Peter Jeremy
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