Date: Fri, 28 Aug 2015 17:16:36 -0453.75 From: "William A. Mahaffey III" <wam@hiwaay.net> To: freebsd-questions@freebsd.org Subject: Re: *Caution: Threadjack !!!!* Backup strategies Message-ID: <55E0DC7A.6000304@hiwaay.net> In-Reply-To: <55E07C7F.80102@freebsd.org> References: <CEAD84AD-341A-4FB9-A3A1-D0D5A550AFFD@lafn.org> <55E047DC.40800@qeng-ho.org> <CAE63ME6mDXpyB7tuRvOr3sDL532fR-BGOD1swY1GoWXXxaAm=w@mail.gmail.com> <55E06B61.7040305@hiwaay.net> <55E07C7F.80102@freebsd.org>
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On 08/28/15 10:27, Matthew Seaman wrote:
> On 08/28/15 15:07, William A. Mahaffey III wrote:
>> Warren's (fabulously lucid) page brings up a question for me. For years
>> I have used a 'pull' strategy for across-the-LAN backups, w/ my 'backup
>> servers' using tar or rsync to access data for backup on NFS-mounted (or
>> automounted) directories that I want backed up. This all happens
>> automatically overnight under cron. I am usually *not* backing up system
>> files, but rather user data, although I have recently started backing up
>> system stuff as well. Warren's page consistently illustrates a 'push'-ed
>> backup, & involves system files. I am *dead* serious about automated
>> backups, no possibility of forgetting to do it that way, but I always
>> thought that trying to backup 'live' system files was a bad idea
>> (right/wrong ?). There doesn't seem to be a way to do a 'push' backup
>> w/o messing with live system files. I guess I am asking about 'best
>> practices' for backups, & the wisdom/validity of backing up 'live'
>> system files. Sorry for rambling, but the question(s) popped up for me
>> while reading Warren's web page. Any input appreciated. Have a nice day
>> & weekend :-).
> Push vs pull strategies are a matter of taste. With a pull strategy,
> almost all the configuration is in one place and the backup server can
> control resource usage -- so it's preferable if you've got a large
> number of machines to back up. Push is usually a bit simpler to script,
> plus it's the only viable way of backing up to eg. a cloud service.
>
> True, you cannot guarantee a coherent backup from a live filesystem.
> Your choices are either to unmount the filesystem (or otherwise render
> it quiescent) or else use some form of snap-shotting.
Can I unmount the root fs (for example) once booted ? I thought not ....
One of the machines I am backing up is a RPiB+ running NetBSD 7.0-beta,
serving as the time server for my LAN. It has only 1 large partition for
root, so I get it all in my backup. Could that be unmounted
(temporarily) for a backup ?
>
> Snapshotting is generally the preferable option, since it avoids
> disrupting the system too much while the backup is happening. The
> built-in native backup mechanisms support this: for UFS, dump(8) has the
> -L flag (except with soft-updates+journalling), and for ZFS, zfs send
> only works on snapshots.
I just checked on the RPi & the '-L' flag has been hijacked to use for
labelling the dump, bummer !!!!
>
> Of course you can always create snapshots manually, mount them somewhere
> and then use whatever tools of your choice to backup the snapshot. This
> is how I use tarsnap(1).
Yeah, but I want automation !!!!
>
> Cheers,
>
> Matthew
>
>
>
--
William A. Mahaffey III
----------------------------------------------------------------------
"The M1 Garand is without doubt the finest implement of war
ever devised by man."
-- Gen. George S. Patton Jr.
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