When there is an incorrect calculation of the required shared memory for Oracle HTTP Server DMS, error logs are displayed. These problems can be resolved by setting the DMS shared memory directive to a value larger than the default value of 4096 or continuing to set the directive 50% higher until the problem is resolved.
An error log containing the string dms_fail_shm_expansion: out of DMS shared memory in pid XXX, disabling DMS; increase DMSProcSharedMem directive from YYY is displayed when an incorrect calculation of required shared memory for Oracle HTTP Server DMS. This can be resolved by setting DMSProcSharedMem to a larger value than the default value of 4096. In some extreme configurations, you might see the following message in the Oracle HTTP Server error log:
dms_fail_shm_expansion: out of DMS shared memory in pid XXX, disabling DMS; increase DMSProcSharedMem directive from YYY
This is because of an incorrect calculation of required shared memory for Oracle HTTP Server DMS. This can be resolved by setting DMSProcSharedMem to a larger value than the default of 4096. Continue setting DMSProcSharedMem 50% higher until the problem is resolved. The minimum value for DMSProcSharedMem is 256 and the maximum value is 65536.
In a configuration with a very large number of virtual hosts (hundreds or thousands), if the above workaround does not work, you can instead, set the environment variable OHS_DMS_BLOCKSIZE to a large enough value that Oracle HTTP Server starts without error. The value of this variable is in kilobytes and a value of 524288 is a good starting point. If the error persists, continue to increase the value by 50% until Oracle HTTP Server starts without error.