HP XP P9500 Storage - Manual (Page 12)

Table 5 Behavior of storage system - block option is “Cache Level” (continued)
Behavior of the XP P9500 disk array Compatible XRC Options
Do not Block is Not specified by SDM (Block
is specified) or Do not Block (Volume Level)
is disabled Do not Block is specified by SDM and Do not
Block (Volume Level) is enabled Setting Option
1. When you specify the [Do not Block] in the Xaddpair command parameter, enable the [Do not Block] in the
Compatible XRC option settings.
2. When you prioritize the retention of XRC pair status, set the [Level 1 Sleep] to Enable and [Level 2 Suspend] to
Disable.
3. When you prioritize the retention of host I/O performance, specify the [Do not Block], or set the [Level 1 Sleep] to
Disable and [Level 2 Suspend] to Enable.
Multiple CLPR use
If you want to use Compatible XRC and more than one cache logical partition (CLPR), we recommend
that you use SC sessions in the same CLPR. Compatible XRC options can be set to each CLPR. If
an SC session extends over more than one CLPR, the storage system operates depending on the
Compatible XRC option setting for each CLPR. For example, if more than one session exists in one
CLPR and the amount of used sidefile capacity in the CLPR reaches level-2 (if the Level 2 Suspend
option of Compatible XRC is enabled) or level-3, the session that occupies the largest capacity in
the sidefile in the cache is suspended.
3390-A and 3390-M devices
To use a 3390-A or 3390-M device as Compatible XRC P-VOL or S-VOL, apply the System Data
Mover (SDM) software at the secondary site with the following PTF (program temporary fix):
[PTF] UA18053: SUPPORT XRC VOLUME SIZE UP TO 65520 CYL
If this PTF has not been applied to the SDM, the 3390-A or 3390-M devices cannot be used as
P-VOLs or S-VOLs in Compatible XRC operations.
Offline microcode replacement or volatile PS on
When offline microcode replacement, which requires PS OFF and PS ON, or volatile PS ON after
the battery has discharged, is performed while Compatible XRC is operating, the storage control
(SC) session of the storage system is automatically terminated. When this session is terminated,
the session of the SDM side of the secondary site is suspended but the following RESUME operation
may fail. To avoid the RESUME failure:
•
Before replacing the microcode offline, delete all Compatible XRC pairs with the XDELPAIR
command before PS OFF, and then create all pairs again with the XADDPAIR command after
PS ON.
•
When performing volatile PS ON, delete all Compatible XRC pairs with the XDELPAIR command
immediately after PS ON, and then create all pairs again with the XADDPAIR command.
Maintenance
When a maintenance operation is needed while Compatible XRC is being used, I/O's for
Compatible XRC pair volumes or Compatible XRC itself should be stopped before the maintenance
operation.
If a maintenance operation must be done while Compatible XRC is being used, before you start
the maintenance operation, confirm that the usage of the Sidefile monitor is less than 20% of total
Cache capacity by monitoring each combination of MPPK and CLPR usage. Do not perform the
maintenance operation unless the Sidefile monitor usage is less than 20% of total Cache capacity.
12 Requirements and restrictions