4.4. Storage and Filesystems
- The NFSv4 server in Red Hat Enterprise Linux 6 currently allows clients to mount using UDP and advertises NFSv4 over UDP with rpcbind. However, this configuration is not supported by Red Hat and violates the RFC 3530 standard.
- If a device-mapper-multipath device is still open, but all of the attached paths have been lost, the device is unable to create a new table with no paths. Consequently, the following unusual output may be returned from the
multipath -ll output
command:mpatha (3600a59a0000c2fd0003079284c122fec) dm-0, size=2.0G hwhandler='0' |-+- policy='round-robin 0' prio=0 status=enabled | `- #:#:#:# - #:# failed faulty running `-+- policy='round-robin 0' prio=0 status=enabled |- #:#:#:# - #:# failed faulty running `- #:#:#:# - #:# failed faulty running
Output of this type indicates that there are no paths to the device. The erroneous lines in the output preceded by the string#:#:#:#
will be removed in a future release. - dracut currently only supports one FiberChannel over Ethernet (FCoE) connection to be used to boot from the root device. Consequently, booting from a root device that spans multiple FCoE devices (e.g. using RAID, LVM or similar techniques) is not possible.
- pvmove cannot currently be used to move mirror devices. However, it is possible to move mirror devices by issuing a sequence of two commands. For mirror images, add a new image on the destination PV and then remove the mirror image on the source PV.
$> lvconvert -m +1 <vg/lv> <new PV> $> lvconvert -m -1 <vg/lv> <old PV>
Mirror logs can be handled in a similar fashion:$> lvconvert --mirrorlog core <vg/lv> $> lvconvert --mirrorlog disk <vg/lv> <new PV>
or $> lvconvert --mirrorlog mirrored <vg/lv> <new PV> $> lvconvert --mirrorlog disk <vg/lv> <old PV>