IBM System Storage DS3000, Programming Manual

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Parameter Description
autoResync
The settings for automatic resynchronization
between the primary logical drives and the
secondary logical drives of a remote-mirror pair.
This parameter has the following values:
v enabled
– Automatic resynchronization is turned
on. You do not need to do anything further to
resynchronize the primary logical drive and the
secondary logical drive.
v disabled – Automatic resynchronization is turned
off. To resynchronize the primary logical drives
and the secondary logical drive, you must run the
resume remoteMirror
command.
writeOrder
The write order for data transmission between the
primary logical drive and the secondary logical
drive. Valid values are
preserved
or
notPreserved
.
writeMode
How the primary logical drive writes to the
secondary logical drive. Valid values are
synchronous
or
asynchronous
.
Notes
You can use any combination of alphanumeric characters, hyphens, and underscores for the names.
Names can have a maximum of 30 characters.
When you choose the primary logical drive and the secondary logical drive, the secondary logical drive
must be of equal or greater size than the primary logical drive. The RAID level of the secondary logical
drive does not have to be the same as the primary logical drive.
Product shipments using the DS4800 (Models 82, 84, 88) or DS5100, DS5300 controller define a maximum
of 128 remote mirrors. The DS4700 Model 70 and DS4700 Model 72 controllers can define a maximum of
64 remote mirrors.
Passwords are stored on each storage subsystem in a management domain. If a password was not
previously set, you do not need a password. The password can be any combination of a alphanumeric
characters with a maximum of 30 characters. (You can define a storage subsystem password by using the
set storageSubsystem
command).
Synchronization priority defines the amount of system resources that are used to synchronize the data
between the primary logical drive and the secondary logical drive of a mirror relationship. If you select
the highest priority level, the data synchronization uses the most system resources to perform the full
synchronization, which decreases performance for host data transfers.
The writeOrder parameter applies only to Enhanced Global Mirrors and makes them become part of a
consistency group. Setting the writeOrder parameter to preserved causes the remote-mirror pair to
transmit data from the primary logical drive to the secondary logical drive in the same order as the host
writes to the primary logical drive. In the event of a transmission link failure, the data is buffered until a
full synchronization can occur. This action can require additional system overhead to maintain the
buffered data, which slows operations. Setting the
writeOrder
parameter to
notPreserved
frees the system
from having to maintain data in a buffer, but it requires forcing a full synchronization to make sure that
the secondary logical drive has the same data as the primary logical drive.
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IBM System Storage DS3000, DS4000, and DS5000: Command Line Interface and Script Commands Programming Guide