6.0 HP X9000 File Serving Software File System User Guide (TA768-96043, October 2011)

On the CLI, use the ibrix_fs command to extend a file system. Segments are added to the file
serving nodes in a round-robin manner. If tiering rules are defined for the file system, the -t option
is required. Avoid expanding a file system while a tiering job is running. The expansion takes
priority and the tiering job is terminated.
Extend a file system with the logical volumes (segments) specified in LVLIST:
ibrix_fs -e -f FSNAME -s LVLIST [-t TIERNAME]
Extend a file system with segments created from the physical volumes in LVLIST:
ibrix_fs -e -f FSNAME -p PVLIST [-t TIERNAME]
Extend a file system with specific logical volumes on specific file serving nodes:
ibrix_fs -e -f FSNAME -S LV1:HOSTNAME1,LV2:HOSTNAME2...
Rebalancing segments in a file system
Segment rebalancing involves redistributing files among segments in a file system to balance
segment utilization and server workload. For example, after adding new segments to a file system,
you can rebalance all segments to redistribute files evenly among the segments. Usually, you will
want to rebalance all segments, possibly as a cron job. In special situations, you might want to
rebalance specific segments. Segments marked as bad (that is, segments that cannot be activated
for some reason) are not candidates for rebalancing.
The rebalancing feature can also evacuate segments (or logical volumes) located on storage that
will be removed from the cluster. This procedure moves the data to other segments in the file system,
and is transparent to users or applications accessing the file system. For more information about
removing storage from a cluster, see the administration guide for your product.
A file system must be mounted when you rebalance its segments.
How rebalancing works
During a rebalance operation on a file system, files are moved from source segments to destination
segments. X9000 Software calculates the average aggregate utilization of the selected source
segments, and then moves files from sources to destinations to bring each candidate source segment
as close as possible to the calculated utilization threshold. The final absolute percent usage in the
segments depends on the average file size for the target file system. If you do not specify any
36 Maintaining file systems