Backup Central

Folks,

Have been using rsnapshot for some time, generally it's a great tool and has saved my bacon a few times. Thanks, developers!

I have a suggestion regarding a new feature: rsync has a --checksum flag which causes it to fully checksum its transfer. This is useful as a 'belt-and-braces' feature to make sure that comparisons are done on the full file content rather than just date and time, with gives the extra confidence that files have been transferred correctly. It's handy, but quite inefficient. It would be nice to use this flag on (say) every 7 backups (i.e. weekly, if you backup daily), but not every day.

Would be interested in your thoughts, or if this is achieveable with rsnapshot as-is (I haven't found a way).

Thanks,
Andrew.
--
Andrew Ferrier
andrew.ferrier < at > gmail.com ([email]andrew.ferrier < at > gmail.com[/email])

On Wed, 20 Jan 2010, Andrew Ferrier wrote:

Folks,

Have been using rsnapshot for some time, generally it's a great tool and has
saved my bacon a few times. Thanks, developers!

I have a suggestion regarding a new feature: rsync has a --checksum flag
which causes it to fully checksum its transfer. This is useful as a
'belt-and-braces' feature to make sure that comparisons are done on the full
file content rather than just date and time, with gives the extra confidence
that files have been transferred correctly. It's handy, but quite
inefficient. It would be nice to use this flag on (say) every 7 backups
(i.e. weekly, if you backup daily), but not every day.

Would be interested in your thoughts, or if this is achieveable with
rsnapshot as-is (I haven't found a way).


How about setting up two rsnapshot configs, one with --checksum enabled,
the other without, and then setting up the cron jobs similar to

0 23 * * 1-6 rsnapshot -c standard_rsnapshot_rc
0 23 * * 0 rsnapshot -c checksum_rsnapshot_rc

You can probably make this neater using the include_conf to maintain a
standard config file and then two other configs just holding the command
passing long args to rsync and then including the main one. Hope I haven't
got completely the wrong end of the stick.

Freddie


Thanks,
Andrew.

--
Andrew Ferrier
andrew.ferrier < at > gmail.com


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On Wed, Jan 20, 2010 at 2:58 AM, Andrew Ferrier
<andrew.ferrier < at > gmail.com> wrote:
I have a suggestion regarding a new feature: rsync has a --checksum flag
which causes it to fully checksum its transfer. This is useful as a
'belt-and-braces' feature to make sure that comparisons are done on the full
file content rather than just date and time, with gives the extra confidence
that files have been transferred correctly. It's handy, but quite
inefficient. It would be nice to use this flag on (say) every 7 backups
(i.e. weekly, if you backup daily), but not every day.

I've been thinking about this for awhile, too, because if you wait
long enough, you will find errors in files. But I don't know if it
resolves that issue. If a file has been stable for a long period,
then --checksum will just make sure that the file on the backup system
is the same as the file on the main system. But it wouldn't be able
to tell you which one is the CORRECT version (either system could have
had bit-rot). I think what you need is separate checksum records
which are periodically verified for correctness.

-scott

------------------------------------------------------------------------------
Throughout its 18-year history, RSA Conference consistently attracts the
world's best and brightest in the field, creating opportunities for Conference
attendees to learn about information security's most important issues through
interactions with peers, luminaries and emerging and established companies.
http://p.sf.net/sfu/rsaconf-dev2dev
_______________________________________________
rsnapshot-discuss mailing list
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https://lists.sourceforge.net/lists/listinfo/rsnapshot-discuss

On Wed, Jan 20, 2010 at 10:29 AM, Scott Hess
<scott+rsnapshot < at > doubleu.com> wrote:
On Wed, Jan 20, 2010 at 2:58 AM, Andrew Ferrier
<andrew.ferrier < at > gmail.com> wrote:
I have a suggestion regarding a new feature: rsync has a --checksum flag
which causes it to fully checksum its transfer. This is useful as a
'belt-and-braces' feature to make sure that comparisons are done on the full
file content rather than just date and time, with gives the extra confidence
that files have been transferred correctly. It's handy, but quite
inefficient. It would be nice to use this flag on (say) every 7 backups
(i.e. weekly, if you backup daily), but not every day.

I've been thinking about this for awhile, too, because if you wait
long enough, you will find errors in files.  But I don't know if it
resolves that issue.  If a file has been stable for a long period,
then --checksum will just make sure that the file on the backup system
is the same as the file on the main system.  But it wouldn't be able
to tell you which one is the CORRECT version (either system could have
had bit-rot).  I think what you need is separate checksum records
which are periodically verified for correctness.

-scott

Use a separate "include" file. Change its contents once a week, as
part of the weekly snapshot procedures. This is part of how I scripted
things to backup particular large targets who didn't need nightly
backup, but who overall needed the same configuration files.

------------------------------------------------------------------------------
Throughout its 18-year history, RSA Conference consistently attracts the
world's best and brightest in the field, creating opportunities for Conference
attendees to learn about information security's most important issues through
interactions with peers, luminaries and emerging and established companies.
http://p.sf.net/sfu/rsaconf-dev2dev
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rsnapshot-discuss mailing list
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