Date: Thu, 10 Jul 2008 21:23:58 +0200 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-fs@freebsd.org Subject: Re: Storing UFS snapshots externally? Message-ID: <g55nkh$cgf$1@ger.gmane.org> In-Reply-To: <48765802.9060502@audilis.com> References: <48765802.9060502@audilis.com>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigA775BEB77B91DB4D333D9DF6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Daniel E. Lynn wrote: > Greetings all, >=20 > First, let me apologize if this has been asked before. If it has then m= y=20 > search skills must be lacking because I couldn't seem to find it in the= =20 > lists anywhere. >=20 > I'm wondering if it is feasible to store snapshots for UFS on a separat= e=20 > drive, and if so if there is an advisable way of doing it. The basic=20 > idea is that I'd like to be able to mitigate any write overhead of usin= g=20 > a lot of snapshots by using a separate disk for them entirely. Here's=20 > the proposed setup: >=20 > FreeBSD (/) is on ad0 > Homedirs and userdata (/data) is on gm0 (ad2+ad3 mirrored) >=20 > I've been successfully using snapshots for /data, and the overhead on=20 > this system doesn't seem too bad (yet) but if I have more than a dozen = > snapshots, I get the feeling it could get messy. It'd be great if I=20 > could store the snapshots for /data on / someplace.=20 UFS snapshots don't copy the data into the "snapshot" file - they just=20 adjust internal references in the file system. The big file you get when = you create the snapshot isn't really a file in the traditional sense -=20 it consists of file system internal pointers to real data. Simplified,=20 when data gets changed on the "real" file system, *then* the old data=20 gets a separate copy in the snapshot. In short, there's no way other than manually copying (dd, tar) the data=20 from the snapshot to wherever. --------------enigA775BEB77B91DB4D333D9DF6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIdmHPldnAQVacBcgRAhNvAJ4rsx9g2HQkPxU1qy3O3sH0dWkcewCdERdv N4TwMdwkouvPmlfwrC2Y18k= =OGUV -----END PGP SIGNATURE----- --------------enigA775BEB77B91DB4D333D9DF6--
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