User's Manual
HP StorageWorks File System Extender Software user guide 147
Example of resource allocation
The following is an example output of the fsejob --list command, which shows the resource
allocation queue with job priorities. Note that jobs that are currently not waiting for resources do not have
priorities assigned.
Multiple copying
FSE migrates data to FSE media to maintain an offline copy of the data on HSM file systems. Each file on
an HSM file system has a corresponding copy on an FSE medium. The medium that stores such a copy
belongs to the FSE media pool assigned to the respective FSE partition. Therefore all files on a particular
HSM file system are migrated to the same media pool. In case of a disaster, this has the following
advantages:
• A complete HSM file system can be restored from the FSE media, including the file system structure for
the migrated file data.
• The HSM file system restore period is reduced since only the active (online, frequently used) file data
need to be restored.
In order to enhance security and eliminate the risk of physical damage to your media, which can result in
data loss, you can configure FSE to make redundant copies of the file data during migration jobs. To do
this, you need to configure additional media pools, allocate additional media, and assign them to the
particular HSM file system. All media pools must be configured with the same block size (BlockSize
variable in the FSE media pool configuration file).
The number of FSE media pools assigned to the same FSE partition equals the number of copies the data
from that FSE partition will have on FSE media. If you have more copies of file data on FSE media, you are
able to recall your data from any available copy, thus benefiting on recall speed and data safety.
Depending on the configuration of your FSE implementation and availability of required resources, you
can have copies made in parallel or sequentially.
Parallel copying
The number of FSE media pools assigned to an FSE partition determines the number of copies of the
migrated data; you set up parallel copying by configuring at least two drives for the FSE partition (the
MaxNumDrivesMigration variable in the FSE partition configuration file). Note that a media pool
cannot be assigned to multiple partitions.
For best performance, there must be at least n drives free when the migration job with parallel copying
starts, where n is the number of media pools assigned to the partition. Because of that, the number of
parallel copies must not exceed the total number of drives that can be used for migration with the partition
(MaxNumDrivesMigration), neither can it exceed the system-wide number of drives that can be used
for migrations (SystemMaxNumDrivesMigration in the FSE system configuration file). Furthermore, the
number of parallel copies must be balanced with the need for drives for other jobs running in FSE.
If there are not enough free drives available during a migration job with multiple copies, the copies that
cannot be made in parallel will be made sequentially.
cumulus:/root # fsejob -l
JobId Partition Type Prio Started Status
20021119000043 Part01 migration n/a 2002/11/19 08:02:05 writing to medium
20021119000044 Part01 migration 1023 2002/11/19 08:02:40 waiting for resources
20021119000045 Part01 migration 1009 2002/11/19 08:03:15 waiting for resources
20021119000046 Part02 recall 4000 2002/11/19 08:03:38 waiting for resources
20021119000047 Part01 migration 1030 2002/11/19 08:02:40 waiting for resources
20021119000048 Part02 migration 1016 2002/11/19 08:03:15 waiting for resources
20021119000049 Part01 recall n/a 2002/11/19 08:03:38 reading from medium
20021119000050 Part01 migration n/a 2002/11/19 08:04:30 writing to medium