[CentOS] Turn an ext2 filesystem into a component of a mirrored RAID?

Mon Nov 27 20:56:46 UTC 2006
MrKiwi <mrkiwi at gmail.com>

MrKiwi wrote:
> Bart Schaefer wrote:
>> We have a CentOS 3 server with about 300GB of data on an ext2
>> filesystem that we need to mirror onto a new drive, which we're then
>> going to pull out and put into a second server.  A straight
>> disk-to-disk copy (with rsync, tar, or "cp -a" doesn't much matter)
>> manages about 75MB per minute, which would take almost three days, and
>> the system gets very sluggish while such a copy is going on, so we
>> can't afford to just let it run.
>>
>> Is it possible, without loss of data, to convert the existing ext2
>> filesystem into a mirrored software RAID, then add the new drive as a
>> second device and let rebuilding the RAID take care of making the
>> copy?  Even if this took more time, we've had good overall system
>> performance with software RAIDs rebuilding in the background before,
>> so it could run as long as necessary.  We'd then need to be able to
>> remove the second device from the RAID and either convert it back into
>> a plain ext2 or put it into a similar software RAID in the destination
>> machine.
>>
>> Is this possible?  Is there another plan that would make more sense?
>>
>> Thanks in advance for suggestions.
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>>
> Does rsync with the bandwidth limiting features still slow the system 
> unacceptably?
> 
> Just a thought,
> 
> MrKiwi,
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> 
Also - maybe you could add two scheduled scripts;
Fri 8pm, "killall rsync; rsync A B"
Mon 5am, "killall rsync; rsync --bwlimit A B"

Would that give you fast-as-possible syncing without too 
much loss of responsiveness?

D