[Lustre-discuss] how to reuse OST indices (EADDRINUSE)

Andreas Dilger andreas.dilger at oracle.com
Tue Dec 21 15:18:59 PST 2010


On 2010-12-21, at 15:46, Charles Taylor wrote:
> On Dec 21, 2010, at 12:39 PM, Andreas Dilger wrote:
>> This file is at /O/0/LAST_ID (capital 'o' then zero) and should be copied for OSTs you haven't replaced yet, along with the other files.  It can be recreated with a binary editor from the value on the MDS (lctl get_param osc.*.prealloc_next_id) for the 6 OSTs that have already been replaced. Search the list or bugzilla for "LAST_ID" for a detailed procedure.
> 
> This seems to do the trick.   Thank you!.    One important clarification though...on the mds, should we getting the value of prealloc_next_id or prealloc_last_id?    Section 23.3.9 of the 2.0 Ops manual for "How to fix a Bad LAST_ID on an OST" seems to use prealloc_last_id.    Which should we be using?

Using prealloc_next_id is technically more correct for your situation, since the lower-numbered objects have not been precreated on the OST.  If you used prealloc_last_id then the MDS and OSS would assume the lower-numbered objects exist but the clients would get IO errors trying to access them.

Cheers, Andreas
--
Andreas Dilger
Lustre Technical Lead
Oracle Corporation Canada Inc.




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