HP StorageWorks XP Remote Web Console Software - Manual (Page 92)

Table 26 Remote copy I/O statistics (continued)
Description Statistic
Number of asynchronous recordsets. Total number of recordsets
Average transfer rate (kB/sec) for XP Continuous Access Async update copy remote
I/Os. Average transfer rate (kB/s)
Average response time (msec) for asynchronous update copy remote I/Os. Average response (ms)
Number of recordsets that are scheduled for the settlement of sidefile Number of Scheduling Recordset
Number of times recordsets do not arrive during the schedule Scheduling Miss Count
Number of remaining recordsets when the schedule is completed Number of Remained Recordset
Number of job activations of consistency manager Scheduling Attempt Count
Synchronization
Percent completion of initial copy operations. For example, number of synchronized
pairs/total number of pairs. Pair Synchronized (%)
Number of tracks that have not yet been copied by initial copy or resync copy
operations. This applies only when suspended during initial copy or during resync
copy. Out of Synchronous Tracks
Cache
You can select only this option when you select Subsystem Total or CLPR in Select
LU on the Display Item pane. SideFile[%]
The usage monitor graph closes automatically in the following cases:
•
Stopping the usage monitoring function by clicking Stop in the Operation drop-down list, and
clicking Apply.
•
Clicking another tab.
•
Exiting XP Command View Advanced Edition or XP Remote Web Console.
Optimizing XP Continuous Access operations and disk array performance
XP Continuous Access operations result in increased utilization of the disk array's channel resources
because of additional write (remote copy) operations to secondary volumes. The XP Continuous
Access update copy mode (synchronous or asynchronous) determines exactly how the remote copy
operations impact disk array performance as follows:
•
Synchronous copy mode has an additional effect on disk array performance: increased service
and disconnect time for write I/Os to XP Continuous Access P-VOLs due to the delay between
channel-end and device-end. The length of this delay increases as the distance between the
P-VOL and S-VOL increases, so the longest delay occurs when primary and secondary volumes
are the maximum distance apart.
•
Asynchronous copy mode (XP Continuous Access Asynchronous) eliminates all delays associated
with XP Continuous Access Synchronous operations while providing protection for
write-dependent applications if a disaster occurs. Write I/Os for XP Continuous Access Async
P-VOLs are processed the same way as writes for simplex volumes, without any increase in
service or disconnect time. Asynchronous S-VOL updates are performed completely independent
of all host I/O processes at P-VOLs, and there are no restrictions on subsequent read and
write operations to XP Continuous Access Async P-VOLs. The only performance concerns for
XP Continuous Access Asynchronous are:
◦ Ensuring adequate cache resources are available for sidefiles used to store recordsets at
MCUs and RCUs
◦ Ensuring sufficient Fibre Channel paths are defined for copy operations
92 Performing XP Continuous Access configuration operations