On Tue, Oct 18, 2011 at 1:24 PM, Alex Besogonov
[off-list ref] wrote:

Well, I've written a simple utility which TRIMs empty space on MD RAID-1
devices, ext4/3 on RAID-1 are supported. My script was inspired by
raid1ext4trim.sh-1.4 script in hdparm, but my script also supports TRIM on
arbitrary partitioned devices.

Since it calls TRIM on raw devices there is a possibility of really bad data
corruption bugs. So there's test/test.sh script which try to test mdtrim by
creating MD array on a single SSD drive, filling it up with random data and
then TRIMing empty space. So far, it works for me but it would be great to
have more test results.

You can get it here: https://github.com/Cyberax/mdtrim

Nice - I'll have to give this a shot - have you found that SSDs
generally "zero" out the trimmed space so that the mismatch_cnts stay
in sync?

I had worked on modifying the raid1ext4trim.sh to run on MD1 arrays,
but was never brave enough to test it on live data yet and don't have
spare SSDs to use for testing.

-Dave