[Lustre-discuss] orphaned objects on OSTs

[Michael Barnes]

Lustre users,

We've had some hardware and lustre crashes in the recent past, and we are trying some new hardware configurations for performance and hopefully stability reasons.  To make the changes, we first migrate the data off of the respective OSTs, and then do the reconfigure, and put the OSTs back online.

I'm guessing that the MDS simply doesn't know about the dangling object on the OST.  On one OST that I've examined I noticed that most of the orphaned objects are from Oct 27, and somewhere between Oct 26th and 27th the metadata server had a software crash (1.8.1.1 since upgraded to 1.8.4).  I'm guessing that the clients pushed data directly to the OST and could not update the MDT, thus leaving the stray files on the OST.

Is there any way to get more information about the files or possibly clean these files while lustre is active?  All I have are the object ID and regular UNIX metadata information that is stored on the object files.  When these errors occurred, did the write fail on the client side, and are the users' not expecting the data to be there?

Unfortunately, a full lfsck does not seem to be an option due to the amount of time that a full lfsck takes.  I guess we are more than OK with losing the files, more so if the users' got a failed write.

I've seen too many of these stray files for me to ignore them anymore.  If anyone has any tips on how to deal with these orphaned objects, please let me know.

Thanks,

-mb

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| Michael Barnes
|
| Thomas Jefferson National Accelerator Facility
| Scientific Computing Group
| 12000 Jefferson Ave.
| Newport News, VA 23606
| (757) 269-7634
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