Volume Availability During Upgrade
The instructions in this guide show you how to upgrade your SAN’s metadata
controllers one at a time so that existing volumes remain available. As each controller
is upgraded, volumes it is hosting fail over to standby controllers. However, if you
enable extended attributes on a volume after upgrading to Xsan 2.2, the volume is not
mounted on clients until the conversion process finishes. This process can take hours,
depending on the number of files on the volume; the volume is not available during
this time.