[DRBD-user] How to Trim ssd raid+ocfs2+drbd+dual primary?

Lars Ellenberg lars.ellenberg at linbit.com
Thu Jan 9 16:10:29 CET 2014

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Wed, Jan 08, 2014 at 09:56:19PM +0900, trex wrote:
> I built HA iSCSI targets with ocfs2+dual primary.(Ubuntu 13.04)
> Each node has SSD raid with mdadm level0.
> few days later, ocfs2 became frozen sometimes.
> I figured out that it happens without TRIM.
> But, I couldn't TRIM ssd raid because ocfs2 only supports offline TRIM(fstrim) and drbd 8.4.4 only supports online TRIM(discard).

Uhm, to the linux block layer (including DRBD), there is no difference
between what you call "online" or "offline" here.  And whether you call
it trim or discard or unmap, again, to the linux block layer, it is all
the same thing.  The differences are implementation details in the low
level hardware drivers (scsi, fusion, etc.)

Did you actually try it?
What happened?
Error message?

Are you sure your SSD *and* MD properly support and propagate the
discard capabilities and requests?

: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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