Release Notes

22 Limitations
Limitations of CIFS protocol (Samba) usage with FSE implementation
These limitations apply to FSE users that are accessing HSM file systems located on Linux systems using the
CIFS protocol and Samba servers. Samba servers are mostly used by Windows clients.
File transfer blockage between Samba client and server
Samba client processes provide only one thread per session. Therefore, if a Samba client accesses an
offline file on an HSM file system, other transfers between the Samba client and the Samba server are
blocked by the HSM file system filter. Only after the processed file is recalled completely, can another
transfer be made from the same Samba client.
Under certain circumstances this behavior may cause substantial delays in file transfers, especially if files
on non-HSM file systems and offline files on HSM file systems are accessed concurrently using the same
Samba client. Note that users on other Samba clients (Windows systems) are not affected, since such file
transfers are processed for each client separately.
Kernel oplocks may interfere with FSE software
Opportunistic locking, in which the kernel oplocks (also known as file lease), is one of the Samba features
intended to increase file-sharing performance. Opportunistic locking is enabled by default.
The usage of kernel oplocks raises a conflict with the FSE software when recalling an opportunistically
locked file that resides on an HSM file system. To ensure normal FSE implementation operation, the kernel
oplocks feature must be disabled. To disable the kernel oplocks feature, add the line kernel oplocks =
no to the [global] section in the Samba configuration file, which is usually:
or
CAUTION: Disabling the kernel oplocks can cause a decrease in performance when accessing and
transferring via Samba. Note that when kernel oplocks are disabled, accessing the same files locally and
over a Samba share simultaneously may result in unpredictable file contents.
Unwanted recalls from FSE media in Windows Explorer
Windows 95/98/ME systems
While browsing directories with offline files on HSM file systems via Samba, Windows Explorer initiates
the recall process for all files in the browsed directory. In other words, Explorer attempts to read the file
header of each file in the directory and this is recognized as a read event by HSM file system filter.
Consequently, the HSM file system filter triggers a recall.
Windows 2000 systems
Windows 2000 clients are able to correctly recognize offline file attribute if a customized Samba server is
installed on the host machine with the HSM file systems. For more information about the package with the
customized Samba software, refer to the FSE Installation Guide.
Windows NTFS ACLs are not supported through Samba
Windows NTFS Access Control Lists (ACLs) differ from the comparable set of data on Linux. Native access
rights on Linux follow the “owner|group|world – read|write|execute” schema whereas NTFS ACLs
enable, for example, the appointment of delete permissions for individual users. Although it is possible to
configure a Samba server on SUSE LINUX Enterprise Server to support ACLs, note that this is a complex
procedure that depends on the particular network setup (domain controller, user accounts, and so on).
NOTE: The current version of File System Extender does not support migration and recall of ACLs. ACLs
are not recognized by the FSE implementation; therefore, they cannot be migrated to FSE media.
/etc/samba/smb.conf
/usr/local/samba/lib/smb.conf