HP EVA P6000 Software Manual page 25

3. When the command has finished executing, open the file in an ASCII editor. The virtual disk
information will be similar to that shown in
Activity is reported 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 can be a snapshot,
snapclone, or DR group member. In the output, ID (identification) 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 array 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 total from
both controllers.
Table 4 (page 25)
1. Check these values for requests: Read Hit (Req/s), Read Miss (Req/s), and Write (Req/s)
(columns 2, 5 and 8).
2. Look for values in the hundreds. Values in the thousands or tens of thousands indicate a
very active process, such as an active database, that should not be disrupted. If you see
high values for requests during the time period you selected, look for another time period
to perform the upgrade.
Figure 7 Sample virtual disk statistics display
Table 4 HP Command View EVAPerf virtual disk statistics
Counter
Read Hit Req/s
Read Hit MB/s
Read Hit Latency (ms)
Read Miss Req/s
Read Miss MB/s
Read Miss Latency (ms)
lists the statistics you can use to determine the virtual disk activity.
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 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.
The rate at which data is read from physical disks because the data is not present in
the array cache memory.
The average time it takes to complete a read request (from initiation to information
receipt) from the physical disks.
Figure 7 (page 25).
Selecting a time to perform an online upgrade 25