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System behavior – HP XP P9500 Storage User Manual

Page 63

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Suspended types appear on the Detailed Information dialog box. The following lists the Suspended
types and descriptions.

Table 27 Suspended types

Description

Applies to

Types

The user split the pair from the main system using the M-VOL Failure in the
Suspend Type option in the Suspend Kind field. The R-VOL split type is, “by
MCU”.

M-VOL

M-VOL by Operator

The user split the pair from the main or remote system using the R-VOL in the
Suspend Type option in the Suspend Kind field.

M-VOL R-VOL

R-VOL by Operator

The remote system received a request from the main system to split the pair.
The M-VOL split type is Suspended-M-VOL by Operator or Suspended-R-VOL
by Operator.

R-VOL

by MCU

The main system detected that the R-VOL status changed to Simplex because
the user released the pair from the remote system. The pair cannot be
resynchronized because the R-VOL does not have the Suspend status.

M-VOL

Delete pair to RCU

The main system detected an error condition at the remote system (RCU),
that caused the main system to suspend the pair. The R-VOL suspend type is
R-VOL Failure by MCU.

M-VOL R-VOL

by RCU

The main system detected an error during communication with the remote
system, or an error during update copy. In this case, the R-VOL suspend type

M-VOL R-VOL

R-VOL Failure

is usually R-VOL Failure. This suspend type is also used when the number of
paths falls below the minimum number of paths setting on the RCU Option
dialog box.

The main system could not find valid control information in its nonvolatile
memory during IMPL. This condition occurs only if the main system is without

M-VOL R-VOL

MCU IMPL

power for more than 48 hours (i.e., power failure and fully discharged
backup batteries).

The pair was suspended before the initial copy operation was complete. The
data on the R-VOL is not identical to the data on the M-VOL.

M-VOL R-VOL

Initial Copy Failed

The pair was suspended by the CGROUP/FREEZE TSO command.

M-VOL R-VOL

by FREEZE

System behavior

Note the following behaviors for suspended pairs.

The main system stops performing update operations to the R-VOL. It may or may not continue
accepting write I/Os to the M-VOL depending on the M-VOL fence level setting and suspend
option.

If an update fails, the main system maintains exact synchronization by reporting a unit check
and de-committing the M-VOL update. This ensures that both the host system and application
program regard the write operation to the M-VOL as failed.

If the main system accepts subsequent write I/Os for a suspended M-VOL, the system records
the updated data in the M-VOL tracks as differential data. When a suspended pair is
resynchronized, the main system copies the out of sync M-VOL tracks to the R-VOL as differential
data.

Continuous Access Synchronous Z does not allow access to an R-VOL while the pair is
suspended (only when split).

When a pair is suspended, whether user requested or due to failure, the main system generates
sense information to notify the host(s). If the host system supports IBM PPRC (and the PPRC
support RCU option is enabled), this notification results in an IEA494I and/or IEA491E system
console message, which indicates the reason for suspension.

Monitor pair status

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