Date: Wed, 26 Apr 2006 16:29:45 -0400 From: Kris Kennaway <kris@obsecurity.org> To: Eric Anderson <anderson@centtech.com> Cc: freebsd-fs@freebsd.org Subject: Re: Do I need to reserve disk space for UFS snapshots? Message-ID: <20060426202945.GA72171@xor.obsecurity.org> In-Reply-To: <444FD6CB.2080805@centtech.com> References: <444FA4CF.7040507@outblaze.com> <444FD6CB.2080805@centtech.com>
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--W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Apr 26, 2006 at 03:23:39PM -0500, Eric Anderson wrote: > Kent Ho wrote: > >Hi, > > > >I'm planing to use FreeBSD snapshots. It seems to be the snapshop image= =20 > >is placed on the same file system. The question is how do I manage or= =20 > >reserve space for the snapshots? Can someone give me some guidelines or= =20 > >pointers. > > > >Here's my netapp it has a separate area allocated for the snapshots, I'm= =20 > >keeping 2 weekly snapshots in there(weekly.0 & weekly.1) using around 30= G. > > > >Filesystem kbytes used avail capacity Mounted on > >/vol/vol0/ 305052552 272495320 32557232 89% /vol/vol0/ > >/vol/vol0/.snapshot 76263136 30658028 45605108 40%=20 > >/vol/vol0/.snapshot > > > >Filesystem iused ifree %iused Mounted on > >/vol/vol0/ 10802387 89822586 11% /vol/vol0/ > > > >If copy all content in vol0 to a FreeBSD and make 2 snapshot will it be= =20 > >around the same? 272G + 30G =3D 302G? So if I df on the FreeBSD box=20 > >around 302G will be used? > > > >Any help and information is highly appreciated. >=20 >=20 > FreeBSD snapshots do not work the same way as NetApp snapshots. First,= =20 > they must reside on the same filesystem as the snapshotted filesystem.=20 > They will initially eat up some space upon creation equal to the space=20 > used by the cylinder group summaries and superblocks, but it isn't a=20 > whole lot. You'll need to have however much space is changed weekly for= =20 > each snapshot, so if 10Gb per week is changed, then you'll need that=20 > much space per snapshot file done. Also be aware that bad things happen (panics, etc) if your filesystem fills up while snapshots are active! This will hopefully be addressed in a future release. Kris --W/nzBZO5zC0uMSeA Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFET9g4Wry0BWjoQKURAggUAJ9dUZ1sjgUEI0AN/cu1QMnMPHnwcQCgq1OI jFGdc9E8mde7Zp9Ma/YuC/Y= =wr4q -----END PGP SIGNATURE----- --W/nzBZO5zC0uMSeA--
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