Hi Lars and all, >> I have to cross-post to LVM as well to DRBD mailing list as I have no >> clue where the issue is- if it's not a bug... >> >> I can not get working LVM on top of drbd- I am getting I/O erros >> followed by "diskless" state. > For some reason, (some? not only?) VMWare virtual disks tend to pretend > to support "write same", even if they fail such requests later. > > DRBD treats such failed WRITE-SAME the same way as any other backend > error, and by default detaches. Ok, it is beyond my knowledge, but I understand what the "write-same" command does. But if the underlying physical disk offers the command and reports an error when used this should apply to mkfs.ext4 on the device/ partition as well, shouldn't it? drbd detacheds when an error is reported- but why does Linux not report an error without drbd? And why does this only happen when using LVM in-between? Should be the same when LVM is not used.... > Older kernels (RHEL 6) and also older drbd (8.3) are not affected, because they > don't know about write-same. My primary host is running CentOS7 while the secondary ist older (CentOS6). I will try to create the ext4 on the secondary and then switch to primary. > Or tell the system that the backend does not support write-same: > Check setting: > grep ^ /sys/block/*/device/scsi_disk/*/max_write_same_blocks > disable: > echo 0 | tee /sys/block/*/device/scsi_disk/*/max_write_same_blocks > A "find /sys -name "*same*"" does not report any files named "max_write_same_blocks". On none of the both nodes. So I dcan not disable nor verify if it's enabled. I assume no as it does not exist. So this might not be the reason. Greetings Christian _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
