HP XP P9500 Storage - Manual (Page 28)

number, such as 15, copying is faster, but I/O performance of the storage system may
decrease. If you specify a small number, such as 3, copying is slower, but the impact on I/O
performance is lessened.
11. From the Priority drop-down menu, select the scheduling order for the initial copy operations.
You can enter between 1-256. The highest priority is 1, the lowest priority is 256. The default
is 32.
For example, if you are creating 10 pairs and you specified in the System Option window
that the maximum initial copies that can be made at one time is 5, the priority you assign here
determines the order that the 10 pairs are created.
12. From the Difference Management drop-down menu, select the unit of measurement for storing
differential data. You can select Auto, Cylinder, or Track.
With Auto, the system decides whether to use Cylinder or Track. This is based on the size of
the volume.
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If VLL is used, the number of cylinders set for VLL is applied.
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If the pair volume has 10,019 or more cylinders, Cylinder is applied.
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If the pair volume has less than 10,019 cylinders, Track is applied.
13. From the Quorum Disk ID drop-down menu, specify the quorum disk ID that you want to assign
to the pair or pairs.
14. Click Set. The settings display in the Preview area.
15. In the Preview list, check the settings. To change a setting, right-click and select Modify. To
delete a setting, right-click and select Delete. When satisfied, click Apply. This starts pair
creation and initial copying if specified.
Next, you must verify that the pair is recognized by the host, which is described in “Verifying that
the host recognizes new pair” (page 28) . But first, make sure that the pair status is PAIR and that
the Type column in the Pair Operation window shows ESAM for both the primary and secondary
systems. Until the Type column shows ESAM, application I/Os cannot be taken over in case of a
failover.
(RAID Manager does not indicate "ESAM," but indicates "Continuous Access Synchronous" instead.)
Verifying that the host recognizes new pair
The final steps in creating new pairs is to make sure the host recognizes the pair and to verify the
path configuration from the host to the pair. Remember, with ESAM, the host recognizes both P-VOL
and S-VOL as a single volume. This is covered below.
Procedure 9 To recognize a pair from the host:
1. Either reboot the host or use the host operating system's device recognition command. Refer
to the documentation provided with the system.
•
For Linux host operating systems, make sure that the ESAM pair is in the PAIR status before
rebooting. If the host reboots when the ESAM pair is not in the PAIR status, a check
condition might be reported to the host.
•
For Solaris host operating systems, make sure the ESAM pair status is PAIR before
performing the following, otherwise a failure can occur:
- An online operation on a path you are not allowed to access.
- Rebooting the host.
- Dynamic addition of the host device.
- Opening the host device.
If a path becomes offline, change the ESAM pair status to PAIR and then perform the
online operation for the offline path.
28 Pair operations