You can control the space usage of a file system by indicating
how and when files are migrated and recalled.
You can control the following aspects of file migration and recall
on a file system:
- The high and low thresholds for your file system that determine
when threshold migration automatically starts and stops
- The total number of megabytes of data that you can migrate and
premigrate from your file system to Tivoli® Storage
Manager storage
- The file size before it is migrated
- The size of the stub files that remain on your local file system
when you migrate your files
- The order in which eligible files automatically migrate from your
local file system
- The amount of free space the Tivoli Storage Manager for Space Management client maintains on
your local file system
- The minimum size (in megabytes) for a file to qualify for partial
file recall
- The minimum size (in megabytes) for a file to qualify for streaming
recall mode
- The maximum number of files in the space-managed file system.
The information for each file system is stored in the hsmfsconfig.xml file, which is in the appropriate .SpaceMan directory. You can modify
the settings in the hsmfsconfig.xml file with
the dsmmigfs update command. You can also use the dsmmigfs query command to display the settings in this
file.
At any time after you add space management to your local file systems,
you can update the settings, if necessary.
Copy several files into your migrated file system after you add
space management and run the dsmmigrate command.
If you are running open registration, the command prompts you for
your node password and contact information the first time that you
run it.
You can increase file transfer performance by allowing failover
of automatic migration and recall capabilities to source nodes within
a cluster environment.
Changes to space management settings take effect in the following
manner:
- If you change the high and low thresholds or the premigration
percentages for a file system, the new values take effect immediately.
- If you change the stub file sizes, the new values take
effect only for files that are migrated after you change the settings.
- If you reduce the quota, and the data that you currently migrate
exceeds the new quota, any additional files from your file system
do not migrate. Sufficient files must be recalled during automatic
or selective recall to drop the total number of megabytes of migrated
and premigrated data below the new quota.
- If you change the maximum number of files and sufficient space
is available, the current complete file index (CFI) is replaced by
the newly sized CFI. Sufficient space is determined by the available
free space plus the size of the current CFI. If the new value of the maxfiles parameter of the dsmmigfs command
is 0, then the CFI is sized to the maximum required space in the file
system. If the value of the maxfiles parameter
is smaller than the actual number of files in the file system, or
greater than the theoretical limit, then the CFI is sized to the theoretical
limit for the file system.
On GPFS™ file systems, you can use the GPFS policy engine to monitor space thresholds and search for migration
candidates.
For information about configuring GPFS integration with the Tivoli Storage Manager for Space Management
client, see the Tivoli field
guide TSM for Space Management for UNIX-GPFS Integration Part
I: Policy-driven Threshold Migration at https://www.ibm.com/support/docview.wss?uid=swg27018848.