HP 6400/8400 HP StorageWorks Enterprise Virtual Array updating product softwar - Page 30

3. When the command has completed, open the file in an ASCII editor. The virtual disk information will appear similar to that in Figure 6. Activity is reported separately for each controller accessing a virtual disk. The total activity for each virtual disk is the sum of the reported activity for each controller. A virtual disk may also be a snapshot, snapclone, or a DR group member. In the output, logical unit number (LUN) is used interchangeably with virtual disk. Virtual disks must be presented to a host to be seen by HP Command View EVAPerf. However, replication volumes on the replication system are visible without being presented. Because the storage system controllers are active/active, one controller is preferred (the owning controller) but requests can still be processed by the other controller (the proxy controller). In active/active controllers, all host requests are logged by the receiving controller only, whether owning or proxy. Thus, all request rate and data rate activity for a virtual disk is the sum of both controllers. The statistics you can use to determine the virtual disk activity are listed in Table 3, in order of the columns on the screen, left to right. 1. Check the values for requests: Read Hit Request (Req/s), Read Miss Request (Req/s), and Write Requests (Req/s). 2. Look for values in the hundreds. When the values are in the thousands or tens of thousands, they indicate a very active process such as an active database that you should not disrupt. If you see high values for request during the period you are checking, look for another time period to perform the upgrade. Figure 6 Sample virtual disk statistics display . Table 3 HP Command View EVAPerf virtual disk statistics Counter Read Hit Req/s Read Hit MB/s Read Hit Latency Read Miss Req/s Description The number of read requests per second completed from the array cache memory. Data may reside in the cache memory due to a previous cache miss or because of a prefetch operation generated by a sequential read data stream. The rate at which data is read from the array cache memory because of read hit requests. The average time it takes to complete a read request (from initiation to information receipt) from the array cache memory. The number of read requests (per second) that failed to complete from the array cache memory and were completed from physical disks instead. 30 Pre-upgrade tasks