Copying Pre-Existing Files

Files that existed before their policies had the Alternate Store Location feature enabled are not copied without taking additional steps. It is recommended that the set of these files be added in subsets of the total list, rather than all at once. This allows for optimizing the rate of copy completions by organizing the retrieval of files for a minimum amount of tape handling. When the Alternate Store Location feature encounters a file that is truncated, it will retrieve the file automatically with a small amount of retrieval optimization, but it can end up bottlenecking file copies behind inefficient retrievals when there is a large set of truncated files in the list of files to be copied.

Best practices for the copying of pre-existing files is to:

1. Identify the set of all files you wish to copy that are not already enabled for Alternate Store Location copying.
2. Organize the full set into subsets that can be retrieved efficiently by subset.
3. Retrieve one complete subset of files to disk.
4. After the subset retrieval has completed, submit the subset to the input of the altstoreadd command as described in section altstoreadd, and start the retrieval of another subset of files.
5. Monitor the completion of background copies as described in section altstoremod. When a subset has been copied, truncate the files listed in the subset.