[lustre-discuss] Full OST, any way of avoiding it without hanging?

[Harr, Cameron]

In my brief attempts to use lfs migrate, I found performance pretty slow 
(it's serial). I also got some ASSERTs which should be fixed in 2.10 per 
LU-8807; note that I was using 2.8. On a more trivial level, I found the 
-v|--verbose option to the command doesn't work.


On 01/07/2019 12:26 PM, Mohr Jr, Richard Frank (Rick Mohr) wrote:
>> On Jan 7, 2019, at 2:09 PM, Jason Williams <jasonw at jhu.edu> wrote:
>>
>> One last question, How safe is lfs_migrate?  The man page on the installation says it's UNSAFE for possibly in-use files.  The lustre manual doesn't have the same warning and says something about it being a bit more integrated with the MDS.
>>
>> http://doc.lustre.org/lustre_manual.xhtml#dbdoclet.lfs_migrate
> I have not used lfs_migrate, so I don’t have any direct experience.  From what I have read online, the lfs_migrate script used to just do a copy/rename of the file.  But now it looks like the “lfs” command has a built-in “lfs migrate” subcommand which supports a “—block” option to prevent file access while the migration is happening.  So it might be safe to use.
>
> Perhaps someone else on the list with more experience using this command could chime in.
>
> --
> Rick Mohr
> Senior HPC System Administrator
> National Institute for Computational Sciences
> http://www.nics.tennessee.edu
>
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