This helps a lot. A real world scenario with real answers! thanks Megan.
On Thu, Mar 12, 2009 at 11:22 PM, Ms. Megan Larko <[email protected]> wrote: > Yay! I believe I can answer this one. > > On Thu, Mar 12, 2009 at 9:08 PM, Mag Gam <[email protected]> wrote: >> This was a very interesting thread to read. I too have been in the >> same situation and it really stunk! I just went ahead and restored the >> filesystem 10T :-( >> >> Seeing Andreas at work is art :-) > > Very true. >> >> I have a question about this: >> >> Would the OP get 5/6 of his DATA or FILES? 5/6 of DATA is useless! >> However, 5/6 of Files is amazing. I was under the impression the file >> would even be striped across (even if you don't enable striping). > > If one uses the lustre default striping of 1, then one may retrieve > 5/6 of the files. > > In our case, we set-up lustre with its default stripe value of one, so > when the files were written out each file went to one array of disks > seen by the RAID controller (disks were in essentially dumb JBOD > enclosures). We had two such enclosures fail (Well, one failed and > the second was an "Ooops" thinking it was the failed unit; JBOD > hardware really is not that bad). The damaged OSTs were de-activated > per Lustre Manual (lctl---get NID and deactivate specific NID). The > remaining OSTs were mounted and if I remember correctly the array was > mounted on a Lustre client. The NID de-activation would cause a quick > "EIO"--or such combination of letters--to skip attempting any access > on the de-activated NIDs and continue to operate (be that search or > copy) on the remaining parts of the system. The value stripe=1 causes > Lustre to put an entire file onto one OST. I understand that this is > both a little slower and can use up disk space less efficiently than > striping. As we did not have a good data back-up strategy (we're > improving that now), we felt the striping of one to be our safest > approach to preserve file integrity. > > I hope this helps Mag. Anyone on List, please correct me where I > have made inaccurate statements. >> >> TIA > > megan >> >> >> >> >> On Tue, Mar 10, 2009 at 11:57 AM, Ms. Megan Larko <[email protected]> >> wrote: >>> Hi T.H., >>> >>> I do not envy your situation. I have been in a very similar >>> scenario. Andreas Dilger gave me some very good information on >>> deactivating the bad OST and then copying the remaining good files. >>> It worked for me. >>> >>> The thread is archived in cyber-space under: >>> http://osdir.com/ml/file-systems.lustre.user/2008-06/msg00249.html >>> >>> Good Luck, >>> megan >>> _______________________________________________ >>> Lustre-discuss mailing list >>> [email protected] >>> http://lists.lustre.org/mailman/listinfo/lustre-discuss >>> >> > _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
