Date: Sat, 27 Jan 2007 15:09:30 -0800 (PST) From: "R. B. Riddick" <arne_woerner@yahoo.com> To: Coen "Bröcker" <c.brocker@logic-q.nl>, freebsd-geom@freebsd.org Subject: Re: How do I gmirror slices? Message-ID: <20070127230930.96837.qmail@web30305.mail.mud.yahoo.com> In-Reply-To: <LHEFLGAENILPPDJIHADOCEGBCFAA.c.brocker@logic-q.nl>
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--- Coen Bröcker <c.brocker@logic-q.nl> wrote: > Currently ad4 contains 3 partitions: > ad4s1 swap, / and /var > ad4s2 /usr > ad4s3 /home > I wan't to mirror ad4s1 and ad4s2. I want to stripe ad4s3. Below is my > current slice setup. > So u have another disk? Or do u want to mirror ad4s1 to ad4s2? That would be not so wise (performance, safety)... > Offset Size(ST) End Name PType Desc Subtype > Flags > > 0 63 62 - 12 unused 0 > 63 12578832 12578894 ad4s1 8 freebsd 165 > 12578895 147814065 160392959 ad4s2 8 freebsd 165 > 160392960 425706435 586099394 ad4s3 8 freebsd 165 > 586099395 15309 586114703 - 12 unused 0 > > Before I continue setting up the mirror I want to make sure I've setup my > slices correctly. > Reading the gmirror man page it states that the gmirror utility uses on-disk > metadata (stored in the provider's last sector) to store all needed > information. > Since I'm no expert in understanding disk structures I'm not sure what the > above means. > gmirror/gstripe use the last sector of its consumers for meta data, and provide a device that is one sector shorter than the smalles consumer. E. g.: gmirror(name=X, consumers=(ad99s1(size=1GB), ad77(size=2GB)), size=1GB-512B) > In my case I think I should create the folowing slice setup: > my last partition on ad4s1 must end at 12578893 instead of 12578894. The > next partition should begin at 12578895 and end at 160392958 creating the > space to store metadata. > The problem with an existing installation is, that it is possible that the last sector of ad4s1 and ad4s2 and ad4s3 is used by a file system. So we need to know the bsdlabel of ad4s1 and ad4s2 and ad4s3 in order to give useful advice. I just wonder why u want to stripe (without any safety) the home fs, which contains most likely quite important and difficult to restore data, while u want to mirror (with disk failure protection) the root-fs (/), although u can just put a CD into ur box and restore it... R u sure, that u dont want to mirror ur home fs, too (or graid3 (e. g. 2disks (data) +1disk (parity)) or so)? -Arne ____________________________________________________________________________________ Never miss an email again! Yahoo! Toolbar alerts you the instant new Mail arrives. http://tools.search.yahoo.com/toolbar/features/mail/
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