Hi,
Meantime I've created another md device (just 5GB) and I've redone the
tests. I believe
this is easier and less risky than remounting an used md device.
root [/home2]# mount -l | grep md3
/dev/md3 on /home2 type ext4 (rw,barrier=0)
root [/home2]# dd bs=2M count=64 if=/dev/zero of=test6 conv=fdatasync
64+0 records in
64+0 records out
134217728 bytes (134 MB) copied, 12.3287 s, 10.9 MB/s
So the speed issue is still with us I believe.
Is there some way to check the barrier is really set to 0?
Thanks a lot!
On 10/21/2013 4:53 PM, Zheng Liu wrote:
Hi Andrei,
Could you please disable barrier for ext4 and try your 'dd' test again?
$ sudo mount -t ext4 -o remount,barrier=0 ${DEV} ${MNT}
*WARNING: you could lost your data with barrier=0 when you get a power
failure or cold reset.*
We have met a similar problem that is because some SSDs couldn't handle
barrier command properly.
Regards,
- Zheng
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