If an I/O delay from the server node to a storage system occurs, the user can check for the cause in the storage system by using the methods described below. These are only examples, so all causes of I/O delays cannot be determined by use of these methods.
Identify the time when the I/O processing delay occurred and the access path where the delay occurred.
Use this software to check the Affinity Group number and Logical Volume number of the ETERNUS Disk storage system defined in the target access path.
Using performance management, display and check the target LogicalVolume performance values.
If a response of the LogicalVolume unit takes a long time, check RAID Group performance. If a response of RAID Group also takes a long time, find another Logical Volume belonging to RAID Group, and find the LUNs to which the Logical Volume is allocated. Check the I/O statuses of these Logical Volumes, and check for a heavy load on RAID Group. If there is a heavy load, move the appropriate LogicalVolume to another RAID Group, or take other appropriate action.
