MDS server fails after start
This is written in MDS log /var/log/pstorage/
20-08-13 17:26:50.135 Replaying journal ... 20-08-13 17:26:50.144 journal: failed to open '/pstorage/cluster_name/mds/data/journal.46.sn' (No such file or directory) 20-08-13 17:26:50.144 Fatal: Can't replay journal (-2)
MDS journal file is corrupted\deleted.
If you have another MDS server in Cloud Storage - just re-create the broken MDS server :
If there are no other MDS servers (highly not recommended, rare case) - all the storage data is lost.