Chapter 20 Repairing VOB and View Storage Directory ACLs on Windows

We recommend that you use NTFS-formatted disks for holding VOB and view storage directories on the ClearCase LT server. NTFS file-system objects are protected by Security Descriptors, which contain ownership information and discretionary access control list (DACL). (DACL and ACL are often used to mean the same thing.) FAT file-system objects are not protected in this way. Although the readonly attribute is available in both NTFS and FAT, it is not enforced; that is, it can be removed easily.

On NTFS, the ClearCase storage directory's ownership (its owner and primary group ID) is determined from the storage directory root's Security Descriptor. Because FAT file systems do not support the Security Descriptor, ClearCase creates the identity.sd file to store it. A copy of the storage directory root's Security Descriptor is always stored in the identity.sd file, regardless of the file system type, and the groups.sd file holds the supplementary VOB group list.