Date: Wed, 16 Jun 1999 12:26:35 -0400 From: Christopher Michaels <ChrisMic@clientlogic.com> To: 'Greg Lehey' <grog@lemis.com> Cc: FreeBSD Questions <questions@FreeBSD.org> Subject: RE: What would happen if a vinum drive failed? Message-ID: <6C37EE640B78D2118D2F00A0C90FCB4401105998@site2s1>
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> -----Original Message----- > From: Greg Lehey [SMTP:grog@lemis.com] > Sent: Tuesday, June 15, 1999 9:28 PM > To: Christopher Michaels > Cc: FreeBSD Questions > Subject: Re: What would happen if a vinum drive failed? > > On Tuesday, 15 June 1999 at 16:46:35 -0400, Christopher Michaels wrote: > > Hello, > > I have a simple question... I have a vinum volume that consists of 3 > > concatenated drives. If say.. the 3rd drive were to fail, is the whole > > volume trashed? or just the information on the 3rd drive? > > Is this your configuration? > yes > drive 1 device /dev/da1h > drive 2 device /dev/da2h > drive 3 device /dev/da3h > volume foo > plex org concat > sd size 4g drive 1 > sd size 4g drive 2 > sd size 4g drive 3 > > And you're asking what happens if drive 3 (subdisk foo.p0.s2) dies? > yes > In this case, your drive stays up, your plex (foo.p0) is degraded, and > your subdisk is obviously down. If you're very lucky, you can access > some data on the drive, but effectively this is not a good way to do > things, since you can't control the layout of files in a ufs file > system. > Ok, that's what I wanted to know. I was under the impression that if drive 3 failed the whole volume was then be unavailable. But if the volume would still be available, I assume I could recover what was on drive 1 and drive 2 and then, work from there. Yes I know, and I do keep backups, but if the volume is at least workable I should at least have what's in /usr available to me (since it was the 1st thing I copied to the volume), until I can recover the system. That, and quite frankly it was idle curiosity. > If you want protection against drive failure, you have two choices: > RAID-1 or RAID-5. Corresponding configurations would be: > Nah, not at this point, it's not mission critical. And unfortunately my drives are of different sizes otherwise I would have setup striping. Thanks for the info though. > (RAID-1) > > drive 1 device /dev/da1h > drive 2 device /dev/da2h > drive 3 device /dev/da3h > volume foo > plex org concat > sd size 12g drive 1 > plex org concat > sd size 12g drive 2 > > (RAID-5) > drive 1 device /dev/da1h > drive 2 device /dev/da2h > drive 3 device /dev/da3h > drive 4 device /dev/da3h > volume foo > plex org raid5 512k > sd size 4g drive 1 > sd size 4g drive 2 > sd size 4g drive 3 > sd size 4g drive 4 > > Each of these examples will give you a 12 GB volume, and the failure > of any one drive will not affect availability (though it will affect > performance). The original version uses 12 GB of disk, the RAID-1 > version uses 24 GB, and the RAID-5 version uses 16 GB. > Thanks again for the info, and thanks for vinum, it really has made life a little easier on me. > Greg > -- > See complete headers for address, home page and phone numbers > finger grog@lemis.com for PGP public key > -Chris To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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