[9fans] Venti backups from unix

[9fans] Venti backups from unix

[Anthony Sorace]

I use vac in Plan 9 Ports to back up a bunch of Unix hosts to a Plan 9 venti. I've talked about this several times, including on here at least once or twice, but someone asked me again a day or two ago and I realized I didn't have anything convenient to point to. So I did a lab report:

        http://a.9srv.net/reports/vac-unix.pdf

(also .html or .ms if you prefer!)

There's nothing particularly novel in there, but an example in practice is often helpful. I've been using some variation on this since... 2009 (!!!) and it's been very useful.


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[9fans] Re: Venti backups from unix

[wb.kloke]

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Using vac for Unix backup has some shortcomings.

I, too, used vbackup on FreeBSD (UFS2). Whether the different blocksize (on most disks: 32kB) to 8kB vac default may detrimental, is disputable. Now,  I have moved to ZFS, and a different approach is needed. ZFS's own backup tools are useful only if the backup device is ZFS also. It is not known, wether a zfs-send stream would play nice with venti deduplication, and probably the send-stream files themselve are not very useful.

On a desktop system using a browser like chromium or firefox, we got a lot of files we simply don't want to backup. The browsers, and a lot of other desktop applications, scatter those files over several dot-named directories like .config, .local or .cache.  Excluding dot-named files and directories from backup is a good idea, especially for .ssh, which contains secrets, which are not secret anymore, if backupped.

I find it clumsy to instruct vac to do it right by filenames only. Here is my current exclude file for my own user directory:
> exclude wb.vac
> include .*rc
> include .login
> include .profile
> include .xsession
> exclude .*
> exclude ....[gx]z
> exclude ....bz2
> exclude ....img
> exclude ....iso
> exclude ....zip
> exclude ....tar
> exclude ....t[bgx]z
> exclude ...octave-workspace
> exclude Downloads

A version usable for the /home directory would look like
> include */.*rc
> include */.login
> include */.profile
> include */.xsession
> exclude */.*
> exclude ....[gx]z
> exclude ....bz2
> exclude ....img
> exclude ....iso
> exclude ....zip
> exclude ....tar
> exclude ....t[bgx]z
> exclude ....tmp
> exclude .../temp.*
> exclude ...octave-workspace

I am not really happy with this version, too.
For files other than those in user directories, the restricted vac semantics (no file flags, eg.) will also limit the usefulness of plan9port vac as backup tool. 
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Re: [9fans] Re: Venti backups from unix

[Alexander Schreiber]

On Tue, Dec 17, 2024 at 11:53:12AM -0500, wb.kloke@gmail.com wrote:
> 
> On a desktop system using a browser like chromium or firefox, we got a lot of
> files we simply don't want to backup. The browsers, and a lot of other
> desktop applications, scatter those files over several dot-named directories
> like .config, .local or .cache.  Excluding dot-named files and directories
> from backup is a good idea, especially for .ssh, which contains secrets,
> which are not secret anymore, if backupped.

Except if those ssh keys are used to authenticate to other systems,
are not backed up and then subsequently lost to storage failure, one
might have a somewhat not fun time.

So I recommend splitting your backups into unprotected sets (no damage,
at most mildly irritated if it becomes public) and protected sets
(e.g. ssh keys, financial/medical data, etc), the latter of which
should be encrypted.

Kind regards,
           Alex.
-- 
"Opportunity is missed by most people because it is dressed in overalls and
 looks like work."                                      -- Thomas A. Edison

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