Re: [gentoo-user] USe rsync to backup RAID0 to RAID1?

[Florian Philipp]

Am 16.04.2010 02:03, schrieb Neil Bothwick:
> On Thu, 15 Apr 2010 14:30:04 -0700, Mark Knecht wrote:
>
>>    I would like to back up a mounted RAID0 to a mounted RAID1.
>
> The RAID makes no difference, because rsync works at the filesystem level.
>
>>    Would the following command be appropriate to backup /virdata on
>> RAID0 to /backups on RAID1?
>>
>> rsync -avx /virdata/. /backups/.
>
> Yes, although the use of -v makes it harder to see any errors that may
> occur.
>

You should also consider using --delete to cleanse your backup space
from deleted or renamed files.

>>    It appears that maybe the -a option wouldn't copy the links?
>
> It does.
>
>>    Also, how does rsync handle the backup if the RAID0 directory is
>> active and changing? Will it keep working until there are no
>> differences? Or does it read once and copy?
>
> It reads once, and will generally produce an error if a file has changed
> between scanning and copying. Running rsync repeatedly until it returns
> a 0 status may be worth considering.
>
>

If you have an LVM on top of your RAID, you can also use LVM snapshots
for this. Of course, if a larger write action is going on, you still get
a half baked file.

Hope this helps,
Florian Philipp