Date: Tue, 23 Jan 2007 20:08:00 -0300 From: Fernan Aguero <fernan.aguero@gmail.com> To: Oliver Fromme <olli@lurza.secnetix.de> Cc: freebsd-geom@FreeBSD.ORG Subject: Re: clear metadata using dd? Message-ID: <20070123230800.GA98614@iib.unsam.edu.ar> In-Reply-To: <200701231830.l0NIURmC083278@lurza.secnetix.de> References: <520894aa0701081445i43d76098m418ce695d2133e53@mail.gmail.com> <200701231830.l0NIURmC083278@lurza.secnetix.de>
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+----[ Oliver Fromme <olli@lurza.secnetix.de> (23.Jan.2007 15:41): | | Hi, | | I just noticed this message today, and there's one thing | I don't understand ... | | Fernan Aguero wrote: | > I'm trying to set up two disks to contain both gmirrored and | > gstriped slices. | > | > This is what I'm trying to achieve: | > adxs1, swap | > adxs2, gmirror | > adxs3, gstripe | | Can someone please explain why such a setup makes sense? | | As far as I can tell, the purpose of gmirror is to provide | redundancy in the case of drive failure. I.e. if one | drive fails, the system keeps running happily instead of | crashing. Hi, well, I beg to differ, but with this setup I don't see why the system will crash if one disk fails ... I did several tests, removed one disk, and the system booted and worked fine in degraded mode ... Of course I'm not putting essential stuff in the gstriped device. Here's how my setup looks like: ad4s1b, ad6s1b => swap ad4s2, ad6s2 => gmirror (/, /var, /tmp, /usr) (i.e. base OS) ad4s3, ad6s3 => gstripe (/freebsd, /usr/obj, /distfiles, /scratch) So, as you see, in the gstriped device I've put things that I can afford to lose in case of a crash. The FreeBSD sources can be downloaded again, the stuff in /usr/obj can be made again from the sources, the distfile local mirror can also be made fresh again, and the temp scratch space is not to be used for essential stuff. Does it make sense now? Fernan | But if only part of the disk is mirrored, then the system | will still crash if one drive fails. So what is the point | of using gmirror, if not on whole disks? | | Just wondering. | | Best regards | Oliver | | -- | Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing | Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd | Any opinions expressed in this message may be personal to the author | and may not necessarily reflect the opinions of secnetix in any way. | | With Perl you can manipulate text, interact with programs, talk over | networks, drive Web pages, perform arbitrary precision arithmetic, | and write programs that look like Snoopy swearing. | | +----]
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