[LU-13337] How to detach all files from PCC device

• Status: Resolved
• Project: Lustre
• Affects Version/s: Lustre 2.13.0
• Type: Question/Request
• Priority: Minor
• Reporter: Mahmoud Hanafi
• Assignee: Li Xi
• Resolution: Fixed

Description

If a user writes a large number of files on the PCC device, currently there is no way to get a listing of those cached files. The user must keep track of the files there could be cases where a user may lost track of some files.
Are there plans to add functionality for list of files on the PCC?
Currently, is there a backend way to find all those files? Or to detach all files?

Thanks

Comments

[Peter Jones]

Li Xi could you please advise?

[Li Xi]

Are there plans to add functionality for list of files on the PCC?

The cached files are not maintained in memory (otherwise, the list would cost too much memory). Instead, the cached files can be listed by scanning the directory tree on the PCC device. And we are planing to add scanning tools. And the support for listing these cached files will be easily implemented in the tool, even though that is not the original purpose.

There is already patch that adds the tool. https://review.whamcloud.com/#/c/35230/ And we will need to extend the tool a little bit for this purpose.

Currently, is there a backend way to find all those files?

Even before the tool is ready, we could easily parsing the directory tree of PCC device by writing a simple script, because the directory tree can be accessed as normal file system. "find $PCC_DIR -t f" would list all cached files. And by parsing the path, a script can get the FIDs of the cached files. Please note that a tool/script shouldn't modify the PCC storage, otherwise data loss of the cached Lustre files could happen.

Or to detach all files?

The patch https://review.whamcloud.com/#/c/35230/ will be able to detach all cached files when removing a PCC device.

[Mahmoud Hanafi]

please close this case.