Symptoms

Transient /ddvar space usage increases PURPOSE This article explains why space used in /ddvar may increase temporarily and cause transient space usage alerts. Use this KB (Space Running Low in /ddvar 181452 ) to confirm that the /ddvar space alert is cleared and the /ddvar space usage is currently below the alert threshold.

Cause

CAUSE A temporary alert may be encountered when a DDFS core file is being created. The steps to save a DDFS core file to disk are as follows: The system saves the memory pages for the DDFS process to disk by writing it to an uncompressed file.The system then compresses the file. During the compression process, the original file is present.Once the compression process complets, the uncompressed file is removed. Thus, until the compression process completes, both the uncompressed and compressed files are present. Here is an example: A DDFS process creates a 30GB uncompressed core file, which is not uncommon.The uncompressed core file compresses in a 3:1 ratio; therefore the compressed file will take 10GB of space.The most temporary disk space required in /ddvar is (30GB + 10GB ) 40GB. The /ddvar usage in this example is:Active Tier: Resource Size GiB Used GiB Avail GiB Use% Cleanable GiB ---------------- -------- -------- --------- ---- ------------- /ddvar 132.9 17.5 108.7 14% - During the creation of the DDFS core file, the temporary usage would then jump to (17.5GB + 40GB ) 57.5GB used, which is ~43% used.The same theory above then applies to system core dumps, except that system core dumps are generally larger as the whole of system memory is sometimes required to be saved.Once the uncompressed file is removed, the usage % will obviously decrease. This is why you can sometimes experience temporary alerts.

Resolution

SOLUTION There is no action required if the /ddvar space alert is currently cleared and there is sufficient space available in /ddvar.Refer to Space_Running_Low_in_ddvar_for_System_Maintenance_Activities 181452 KB for further information on how to clean /ddvar if required. Note: If your problem persists after executing the steps in this article, please contact your contracted support provider, Gather an Autosupport 180561 , Upload a Support Bundle (SUB) 180563 and Create a service request REFERENCE Space_Running_Low_in_ddvar_for_System_Maintenance_Activities 181452

Support Cases