User's Manual

hp StorageWorks File System Extender User Guide 113
Maximum wait time for migration (MaxWaitTime)
Minimum number of files for migration (MinNumMigFiles)
Maximum number of files for migration (MaxNumMigFiles)
Minimum size for migration (MinMigSize)
Maximum size for migration (MaxMigSize)
NOTE: A general rule for the migration to start is either there are all MinXxx parameters reached or
there is one MaxXxx parameter reached that will start the migration job. MaxXxx parameters can prevent
FSE from filling up HSM file systems in case your MinXxx parameters are not set properly and the
migration is not started at the right time.
Example situations that trigger migration
There are four distinct situations that trigger a new migration job.
• Situation 1
There were no files added to the list in the last MinWaitTime period of time and there are more than
MinNumMigFiles files on the list and total size of files on the list is at least MinMigSize.
• Situation 2
Definition Maximum wait time for migration; if reached, migration is started immediately. The
interval starts with the first file being added to the empty migration candidate list.
Impact Without this parameter, if new files keep arriving to the migration list fast enough, the
MinWaitTime would never be reached and the files would never get migrated.
MaxWaitTime ensures this does not happen. When the oldest file has been on the list
long enough, migration is started.
Definition Minimum number of files on the migration candidate list before migration is started.
Impact You should define the parameter value according to the characteristics of your file data;
create a rate according to the approximate size of your files. This parameter value should
be higher if your files are small, and vice versa.
Definition Maximum number of files on the migration candidate list; if reached, migration is started
immediately.
Impact Without this parameter, if new files kept arriving to the migration list fast enough, the
MinWaitTime would never be reached and the files would never get migrated.
MaxNumMigFiles ensures this does not happen. When the maximum number of files
for migration is reached, migration is started.
Definition Minimum cumulative size of all files on the migration candidate list before migration is
started.
Impact You should define the parameter value according to the characteristics of your file data;
create a rate according to the approximate size of your files. The recommended value is
above 2 MB in order to provide enough data to keep the tape drives streaming.
Definition Maximum cumulative size of all files on the migration candidate list; if reached, migration
is started immediately.
Impact Without this parameter, if new files kept arriving to the migration list fast enough, the
MinWaitTime would never be reached and the files would never get migrated.
MaxMigSize ensures this does not happen. When the maximum size is reached,
migration is started.