UPDATE STGRULE (Update a storage rule for replicating data)

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Use this command to update a storage rule for a server. The storage rule schedules operations to replicate data to a target server.

Privilege class

To issue this command, you must have system privilege, unrestricted storage privilege, or restricted storage privilege.

Syntax

Parameters

rule_name (Required)

Specifies the name of the storage rule. The name must be unique, and the maximum length is 30 characters.

ACTIVE

Specifies whether the storage rule processing occurs. This parameter is optional. The default is NO. The following values are possible:

No: Specifies that the storage rule is inactive. The storage rule is not processed at the scheduled time.
Yes: Specifies that the storage rule is active. The storage rule is processed at the scheduled time.

MAXSESSions

Specifies the maximum number of data sessions that can send data to a target server. This parameter is optional. The value that you specify can be in the range 1 - 99.

Windows operating systems AIX operating systems The default value is 20.

The default value varies:

If TRANSFERMETHOD=TCPIP, the default value of the MAXSESSIONS parameter is 20.
If TRANSFERMETHOD=FASP, the default value of the MAXSESSIONS parameter is 2.

If you increase the number of sessions, you can improve throughput for the storage pool.

When you set a value for the MAXSESSIONS parameter, ensure that the available bandwidth and the processor capacity of the source and target servers are sufficient.

Tips:

If you issue a QUERY SESSION command, the total number of sessions might exceed the number of data sessions. The difference is because of short control sessions that are used to query and set up operations.
The number of sessions that are used for replication depends on the amount of data that is replicated. If you are replicating only a small amount of data, increasing the number of sessions provides no benefit.

DUration

Specifies the maximum number of minutes that the storage rule runs before it is automatically canceled. You can specify a number in the range 60 - 1440. The default value is unlimited. If you do not specify a value, or if you specify a value of NOLimit, the storage rule runs until it is completed. This parameter is optional.

STARTTime

Specifies the time for the beginning of the window in which the storage rule is first processed. The default is the current time. This parameter is optional. The storage rule runs daily within 5 minutes following the specified time.

Specify one of the following values:

Value	Description	Example
HH:MM:SS	A specific time.	23:30:08
NOW	The current time.	NOW
NOW+HH:MM or +HH:MM	The current time plus the specified number of hours and minutes.	NOW+02:00 or +02:00
NOW-HH:MM or -HH:MM	The current time minus the specified number of hours and minutes.	NOW-02:00 or -02:00

TRANSFERMethod

Specifies the method that is used for server-to-server data transfer. This parameter is optional. You can specify one of the following values:

Tcpip

Specifies that TCP/IP is used to transfer data. This value is the default.

Fasp

Specifies that IBM® Aspera® Fast Adaptive Secure Protocol (FASP®) technology is used to transfer data. Aspera FASP technology can help you optimize data transfer in a wide area network (WAN). If you specify TRANSFERMETHOD=FASP, you override any TRANSFERMETHOD parameters that you specified on the DEFINE SERVER or UPDATE SERVER commands.

Restrictions:

Before you enable Aspera FASP technology, determine whether the technology is appropriate for your system environment and install the appropriate licenses. For instructions, see Determining whether Aspera FASP technology can optimize data transfer in your system environment. If the licenses are missing or expired, operations to protect storage pools fail.
If WAN performance meets your business needs, do not enable Aspera FASP technology.

DESCription

Specifies a description of the storage rule. This parameter is optional.

EXTENTVALidation: Specifies the percentage of total extents on the source replication server that are validated during a replication operation. This parameter is optional.
NOne: Specifies that none of the extents on the source replication server are validated during a replication operation that was initiated by this replication storage rule are validated.
LOw: Specifies that 10% of the total extents that are read from the source replication server during the replication operation that was initiated by this replication storage rule are validated. This is the default value.
HIgh: Specifies that 50% of the total extents that are read from the source replication server during a replication operation that was initiated by this replication storage rule are validated.
ALL: Specifies that all (100%) of the extents that are read from the source replication server during a replication operation that was initiated by this replication storage rule are validated.

Performance considerations:

Extent validation can increase CPU usage, which can affect system performance. The potential impact on performance is more significant if all extents are validated.
If you modify the value of the EXTENTVALIDATION parameter during a replication operation, the change is applied immediately to the validation process.

Note: EXTENTVALidation parameter doesn't apply for OSSM data.

Update a storage rule

Update a storage rule that is named repl_action to specify a start time of 2:15:00 AM and use a maximum of 15 sessions:

update stgrule repl_action maxsessions=15 starttime=2:15:00

Related commands

Table 1. Commands related to UPDATE STGRULE
Command	Description
DEFINE STGRULE (replicating)	Defines a storage rule for replicating data.
DEFINE SUBRULE (replicating)	Defines an exception to a replicating storage rule.
DELETE STGRULE	Deletes storage rules.
QUERY STGRULE	Displays storage rule information.
UPDATE SUBRULE (replicating)	Updates a subrule that is an exception to a replicating storage rule.