Re: [HPDD-discuss] Faster way to get list of files on an OST

I've got a question about locating files on a given OST. First some background. We recently had 1 hard drive failure in conjunction with 2 other drives developing SMART errors in short order on one of our OSS's. This OSS is running hardware RAID6 so we didn't lose the raid array or the OST's (there are 4 OST's on this OSS) but the controller is now reporting that there are some bad stripes on the array. The only way to clear the bad stripes is to reformat the array so we are now in the process of migrating the data off of these OST's. So we got a list of the files on those OST's: lfs find /lustre/ -obd hpfs-eg3-OST002c > oss11ost1 lfs find /lustre/ -obd hpfs-eg3-OST002d > oss11ost2 lfs find /lustre/ -obd hpfs-eg3-OST002e > oss11ost3 lfs find /lustre/ -obd hpfs-eg3-OST002f > oss11ost4

And now we're using lfs_migrate to move the files to other OST's. The migration is ongoing and, fortunately, the data corruption due to the bad stripes seems to be minimal. The intention is that once we think the migration is done, to repeat the lfs find commands to verify the OST's are indeed empty. My question: is there a faster way to get the file list? We ran those lfs find commands in parallel but it took over 12 hours for them to complete and found about 28 million files. The MDT is build on top of LVM so I was imagining something along the lines of taking an LVM snapshot, mounting that read only and extracting the info. But I know nothing about the file system structure so this may not even be possible. Any advice would be appreciated - either about this approach or something else that would be faster.