Hi Zheng,
Thank you for your reply. We can make this test and if it doesn't help
we'll re-enable
the barrier but first I need to ask a few questions:
1. /dev/md2 is mounted on /. So your command should look like this?
$ mount -t ext4 -o remount,barrier=0 /dev/md2 /
In /etc/fstab I have other parameters as well:
noatime,usrjquota=quota.user,jqfmt=vfsv0
Do I also add these like this:
$ mount -t ext4 -o
remount,barrier=0,noatime,usrjquota=quota.user,jqfmt=vfsv0 /dev/md2 /
2. Can the command above be run on an active (very active) cPanel server?
3. How do I re-enable the barrier?
4. What is the probability of data loss in case of cold reboot?
Thanks!
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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