[DRBD-user] Dumb question regarding ""disk-barrier=no"

Lars Ellenberg lars.ellenberg at linbit.com
Thu Apr 25 21:49:59 CEST 2013

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

On Thu, Apr 25, 2013 at 01:59:52PM +0000, Prater, James K. wrote:
> We are using RHEL 6.4 this parameter set in the global common
> configuration file and also on the haresources mount attributes.   The
> question is that I cannot change this parameter on the fly with the
> "mount -o remount,barrier=1".   With "tune2fs -l /dev/drbd0",
> nobarrier is still enabled.    The question is, does  this parameter
> propagates into the EXT4 attribute stack?    Or do I have to clear it
> in both drbd and the mount.

Please don't hijack threads.

The DRBD setting "barrier" has nothing to do with the file system mount
option "barrier" -- other than that, if no volatile caches are involved,
it is safe (and usually a performance gain) to disable both of them.

You change the DRBD setting in the DRBD configuration,
or with drbdadm/drbdsetup.

You change mount options via fstab, or tune2fs and equivalents,
and remount.

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

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