Network settings – Suppression of cache.

 

When using programs based on the Borland Database Engine (BDE) it might in some occasions occur that data from a workstation does not reach the disk on the server. This is due to local data caching. Local cache mechanisms must therefore be suppressed in the widest possible extent in order to prevent data loss and corrupted index files.

 

The system registry must be altered to the below mentioned settings. If you are not familiar with system registry editing then don’t. As caching has been introduced for performance reasons, removal of this may slow down your system.

 

Settings on workstations

 

Windows 95 or 98

·      HKey_Local_Machine\System\CurrentControlSet\Services\VxD\VREDIR\DiscardCacheOnOpen = 01

·      HKey_Local_Machine\System\CurrentControlSet\control\FileSystem\SoftCompatMode = 00,00,00,00

·      HKey_Local_Machine\System\CurrentControlSet\control\FileSystem\AsyncFileCommit = 01

·      HKey_Local_Machine\System\CurrentControlSet\control\FileSystem\DriveWriteBehind = 00,00,00,00

 

The registry values for Windows 95 and 98 are all of type ”binary”.

 

Windows NT:

·      HKey_Local_Machine\System\CurrentControlSet\Services\Rdr\Parameters\UseWriteBehind = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\Lanmanworkstation\Parameters\UtilizeNTCaching = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\Lanmanworkstation\Parameters\UseOpportunisticLocking = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\EnableOplocks = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\CachedOpenLimit = 00

 

Windows 2000 or XP:

·      HKey_Local_Machine\System\CurrentControlSet\Services\MRXSmb\Parameters\OplocksDisabled = 01

·      HKey_Local_Machine\System\CurrentControlSet\Services\Lanmanworkstation\Parameters\UseOpportunisticLocking = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\EnableOplocks = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\CachedOpenLimit = 00

 

Settings on servers

 

Windows NT, 2000 or XP:

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\EnableOpLocks  = 00

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\EnableOpLockForceClose = 01

·      HKey_Local_Machine\System\CurrentControlSet\Services\LanmanServer\Parameters\CachedOpenLimit = 00

 

The registry values for Windows NT, 2000 and XP are all of type ”dword”.

 

References:

  1. Microsoft knowledge base articles: Q296264, Q126026, Q163401
  2. On the internet: www.bdesupport.com/stability.htm