On Feb 3, 2026, at 06:01, Huijun Wu <[email protected]> wrote: > I recently encountered an issue related to cross-version mounting of an MDT. > After an MDS crash, I rebooted the MDS and accidentally mounted an MDT that > was originally created and used with Lustre 2.15.4 using Lustre 2.16.1. After > this, I noticed that many files and directories were shown as “????” on the > client side. > I then ran lfsck on this MDT, and found that some directories that originally > belonged to this MDT disappeared entirely. > Any recommendations on how to analyze, recover, or mitigate this issue?
There definitely shouldn't be any issues upgrading from a 2.15 MDT to a 2.16 MDT, and this is tested regularly during normal Lustre development. Did you have any unusual features enabled in Lustre or ldiskfs? Was the filesystem originally formatted with 2.15, or was it formatted with an older version and upgraded already? Were there error messages on the MDS or client console when accessing the problematic files? Cheers, Andreas --- Andreas Dilger Principal Lustre Architect [email protected] _______________________________________________ lustre-discuss mailing list [email protected] http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
