HowTo: Permanent Migration to dCache Read Only Pools

Source pools

• Add the following line to your ${pool.path}/setup file, or alternatively execute this command from the pool admin console.

• If you want permanent changes, remember to run save at the end only when executing this command from the pool admin console. This way is equivalent to write the below information in the ${pool.path}/setup file.
• If you just add the line in the ${pool.path}/setup, please remember to execute reload -yes on the pool admin console, or just the command from there.

migration cache -permanent -pins=keep -concurrency=1 -atime -accessed=0..600 -select=random -include=dc052_1,dc053_1 -target=pgroup \
  -exclude=dc021*,dc022*,dc029*,dc031*,dc037*,dc040*,dc044* -id=caching_recently_accessed_files -verify -size=1070000.. -- pgroup-cms-ro

• Options:

• Filter options:

• -accessed=<string>: Only copy replicas accessed n seconds ago, or accessed within the given, possibly open-ended, interval. E.g. -accessed=0..60 matches files accessed within the last minute; -accesed=60.. matches files accessed one minute or more ago.
• -select=proportional|random: Determines how a pool is selected from the set of target pools. Defaults to proportional.

• proportional: selects a pool with a probability proportional to the free space.
• random: selects a pool randomly.

• Lifetime options:

• -permanent: Mark job as permanent.

However, you need to ensure that the command is set in the ${pool.path}/setup file. Otherwise on a pool restart it will not run it.

• Target options:

• -exclude=<glob>[,<glob>]<...>: Exclude target pools matching any of the patterns. Single character (?) and multi character (*) wildcards may be used.

This option is set to avoid RW pools being included in case that something is miss-configured from the poolmanager side.

• -include=<glob>[,<glob>]<...>: Only include target pools matching any of the patterns. Single character (?) and multi character (*) wildcards may be used.

This option is set to ensure that only some specific pools will be included in case that something is miss-configured from the poolmanager side.

• -target=pool|pgroup|link: Determines the interpretation of the target names. Defaults to pool.

We should setup pgroup because generally we will not want to migrate to a specific pool.

• Transfer options:

• -verify: Force checksum computation when an existing target is updated.
• -atime: Maintain last access time.

Otherwise if file is not used by the client updating the last access time would mean that file will not be recycled first. We want to keep cached hot files and not older ones.

• -pins=keep|move: Controls how sticky flags owned by the pin manager are handled.

• move: Ask pin manager to move pins to the target pool.
• keep: Keep pin on the source pool. Defaults to keep.

• -concurrency=<int>: Specifies how many concurrent transfers to perform. Defaults to 1.

You can setup higher values if you expect a very good performance, otherwise migration can become a bottleneck.