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2.2.17 Journal Corruption in Virtualized Systems

On virtualized systems that are built on Xen version 3, including all releases of Oracle VM 2 including 2.2.2 and 2.2.3, disk synchronization requests for ext3 and ext4 file systems result in journal corruption with kernel messages similar to the following being logged:

blkfront: barrier: empty write xvda op failed
blkfront: xvda: barrier or flush: disabled

In addition, journal failures such as the following might be reported:

Aborting journal on device xvda1

The workaround is to add the mount option barrier=0 to all ext3 and ext4 file systems in the guest VM before upgrading to UEK R3. For example, you would change a mount entry such as:

UUID=4e4287b1-87dc-47a8-b69a-075c7579eaf1  /  ext3  defaults  1 1

so that it reads:

UUID=4e4287b1-87dc-47a8-b69a-075c7579eaf1  /  ext3  defaults,barrier=0  1 1

This issue does not apply to Xen 4 based systems, such as Oracle VM 3. (Bug ID 17310816, 17313428)