HP UX Common Internet File System (CIFS) Client/Server Software manual

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benefit is improved security, but in most cases the additional checks will be redundant to the application checks, and the cost will be reduced performance due to the extra overhead of checking for locks on every read and write.

CIFS/9000 enables strict locking on a per-share basis in the smb.conf file:

[share_name]

strict locking = yes

The default is “no”.

Blocking locks enables the smbd to recognize a timeout period specified on a LockFileEx call. If a previous lock is encountered by a client attempting a byte range lock, the smbd will wait (block) for the timeout period to expire before failing the lock. If the previous lock is released before the timeout, the smbd will then grant the pending lock. When disabled, the lock request is failed immediately.

CIFS/9000 disables blocking locks on a per -share basis in the smb.conf file:

[share_name] blocking locks = no

The default is “yes”.

5.3.OPPORTUNISTIC LOCKING (Oplocks) is implemented by the

CIFS/9000 server on a per-share basis in the smb.conf file. CIFS/9000 Oplock functionality operates just like Windows. Oplocks are enabled by default for each share, which allows the Windows client to cache a local copy of a file for:

Read-ahead

Write-caching

Lock caching

CIFS/9000 disables Oplocks on a per -share basis in the smb.conf file:

[share_name] oplocks = no

The default is “yes”. The default oplock type is Level1.

CIFS/9000 enables Level2 Oplocks on a per -share basis in the smb.conf file:

[share_name]

level2 oplocks = yes

The default is “no”. Oplocks must also be set to “yes” for the Level2 oplock parameter to function.

Oplocks apply to Windows clients only. File sharing issues arise when concurrent file access occurs between Windows clients and UNIX clients, PC-NFS clients, or on files that have been NFS-mounted. A key issue with sharing files between UNIX/NFS, PC-NFS, and

Windows clients is that a Windows client can request an Oplock from the CIFS/9000 server and be granted the Oplock (thus caching the file locally), but a

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Contents E0300 Version 1.03 SeptemberEric Roseme Snsl Advanced Technology Center Legal Notices Copyright NoticesContents Introduction CIFS/9000 Product Overview File Locking Overview ACLPage File Locking Implementations Windows CifsPage Unix NFSPC NFS Mandatory Share Mode Locking Open Mode CIFS/9000 File Locking ImplementationPage Page Page Windows only Client Access Local File System CIFS/9000 File Locking Interoperability ExamplesPage Windows only Client Access NFS Mounted File System Page Windows and Unix Client Access Local File System Page Windows and Unix Client Access NFS Mounted File System Page UNIX/NFS PC-NFS Page Unix PC-NFS Page Clients Page Byte Range Locking Mandatory Share Mode Open Mode CIFS/9000CIFS/9000 Locking Summary OplocksCIFS/9000 Competition Locking Summary Mandatory Share Mode Open Mode Network AppliancePage Mandatory Share Mode Open Mode EMC Celerra EMC CelerraPage Auspex NeTservices Mandatory Share Mode Open Mode Auspex NeTservicesPage Mandatory Share Mode Open Mode Veritas FSE Veritas File Server EditionLocking Summary Table EMCCIFS/9000 File Locking Interoperability Summary Page Smb.conf for Windows-Only Access Appendix a smb.conf ExamplesSmb.conf for Mixed-Mode Access Appendix B Sales Tool Locking Technology Examples Determine Locking RequirementByte Range Locking CIFS/NFS Open Mode Locking CIFS/NFS Open Mode Locking Competitor’s Claims for NFS Non-Locking Protection
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