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I'm noticing the following lines in dmesg when an XFS volume is being mounted

dm-1: Disabling barriers, trial barrier write failed

Anyone know what this means?

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You should modify the mount options. Add nobarrier to the options in /etc/fstab for the partition.

See Red Hat's note about it.

To mitigate the risk of data corruption during power loss, some storage devices use battery-backed write caches. Generally, high-end arrays and some hardware controllers use battery-backed write cached. However, because the cache's volatility is not visible to the kernel, Red Hat Enterprise Linux 6 enables write barriers by default on all supported journaling file systems.

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Thanks! very helpful – wjimenez5271 Apr 3 '12 at 23:38
nobarrier also massively increases performance and you don't get so many flush kernel threads using valuable resources. – Tom O'Connor Oct 31 '12 at 15:49

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