Raid 5 (was: Mounting of Linux volumes)

Nicholas Leippe nick at byu.edu
Thu Dec 1 22:45:22 MST 2005


On Thursday 01 December 2005 10:02 pm, Ross Werner wrote:
> On Thu, 1 Dec 2005, Nicholas Leippe wrote:
> > As for rsync'ing an entire drive, are you doing so with the source drive
> > mounted rw?  Cause if so, you may not get a 'snapshot' of the drive.
> > Depending on the apps using the drive, this could cause serious problems.
>
> In my case, I'm primarily backing up data partitions--I'm not so concerned
> about the Linux install or the applications themselves. For things like
> databases I dump to an SQL file before I do the backup anyway (it's a
> beast to restore databases from the actual data files the db uses, when
> it's even possible).
>
> Out of curiousity, what sort of apps could cause serious problems when
> rsyncing a drive mounted rw?

Any application that relies on the coherency of multiple, volatile files--ie 
they correlate differently over time.

- databases
- any application that produces temporary files (web server session
  data, perhaps?)

I'm sure there are others.

This is the reason point-in-time backup systems are so expensive--it's a
very difficult problem to solve in a manner that is completely transparent
to running processes.

-- 
Respectfully,

Nicholas Leippe
Sales Team Automation, LLC
1335 West 1650 North, Suite C
Springville, UT  84663 +1 801.853.4090
http://www.salesteamautomation.com

-- 
Respectfully,

Nicholas Leippe
Sales Team Automation, LLC
1335 West 1650 North, Suite C
Springville, UT  84663 +1 801.853.4090
http://www.salesteamautomation.com



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