At system startup, the value of a static system parameter
controls whether the file system uses a data cache, and if so, which
data cache it uses (XFC or VIOC). The system parameter depends on
the operating system, as shown in the following table:
In an OpenVMS Cluster, if file system data caching is disabled
on one node, it is disabled throughout the cluster. The other nodes
in the cluster cannot use XFC or VIOC until that node leaves the
cluster or reboots with VCC_FLAGS or VBN_CACHE_S set to a non-zero
value. You can use the DCL command SHOW MEMORY to determine whether caching is enabled.
To disable caching clusterwide, follow these steps on any
node in your OpenVMS Cluster:
Set the appropriate
system parameter (VCC_FLAGS or VBN_CACHE_S) to 0, using MODPARAMS.DAT.
Run AUTOGEN to ensure that other system parameters
allow for the new value. This is not essential, but it is advisable.
You must reboot the system to make the new value
effective.