On Thu, Jan 25, 2018 at 10:32:24PM +0000, Eric Robinson wrote: > Here is a WEIRD one. > > Why would one drbd volume be trimmable and the other one not? > > Here you can see me issuing the trim command against two different > filesystems. It works on one but fails on the other. > > ha11a:~ # fstrim -v /ha01_mysql > /ha01_mysql: 0 B (0 bytes) trimmed > > ha11a:~ # fstrim -v /ha02_mysql > fstrim: /ha02_mysql: the discard operation is not supported > > Both filesystems are on the same server, two different drbd devices on > two different mdraid arrays, but the same underlying physical drives.
The backend on the peer(s) are similar as well? Anything suspicious DRBD related in the kernel log? > Yet it can be seen that discard is enabled on drbd0 but not on drbd1... > > NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO > sda 0 512B 4G 1 > ├─sda1 0 512B 4G 1 > │ └─md0 0 128K 256M 0 > ├─sda2 0 512B 4G 1 > │ └─md1 0 128K 256M 0 > ├─sda3 0 512B 4G 1 > ├─sda4 0 512B 4G 1 > ├─sda5 0 512B 4G 1 > │ └─md2 0 1M 256M 0 > │ └─drbd0 0 1M 128M 0 > │ └─vg_on_drbd0-lv_on_drbd0 393216 1M 128M 0 Why this odd alignment? LVM meta data size of 640k? Try 1M :-) > └─sda6 0 512B 4G 1 > └─md3 0 1M 256M 0 > └─drbd1 0 0B 0B 0 > └─vg_on_drbd1-lv_on_drbd1 0 0B 0B 0 -- : Lars Ellenberg : LINBIT | Keeping the Digital World Running : DRBD -- Heartbeat -- Corosync -- Pacemaker DRBD® and LINBIT® are registered trademarks of LINBIT __ please don't Cc me, but send to list -- I'm subscribed _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user