Access to the file system will hang when having large number of CIFS/NFS shares configured on Symantec FileStore Server (SFS). In one situation, the hang was observed when having around 400 shares.
Symantec engineering has identified the defect in VxFS module which causes indefinite locking.
This is tracked via Symantec etrack incident # 2481984.
This issue is fixed in VxFS 5.0MP4HFu patch.
VXFS 5.0MP4HFu hotfix will be available as part of SFS 5.6RP1P1 patch.