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

Bart Schaefer barton.schaefer at gmail.com
Mon Nov 27 20:13:33 UTC 2006

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

Is this possible?  Is there another plan that would make more sense?

Thanks in advance for suggestions.

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