PROTECT STGPOOL (Protect data that belongs to a storage pool)

Use this command to protect data in directory-container storage pools by storing the data in another directory-container storage pool on the target server.

When you issue this command, data that is stored in the directory-container storage pool on the source server is backed up to a directory-container storage pool on the target server. By protecting the directory-container storage pool, you can repair damaged storage pools by using the REPAIR STGPOOL command.

Issue this command on the server that is the source server for data.

Prerequisite: For the storage pool that is being protected, you must specify the target pool by using the PROTECTSTGPOOL parameter on the DEFINE STGPOOL or UPDATE STGPOOL command.

When you regularly use the PROTECT STGPOOL command, you can typically reduce the processing time for the REPLICATE NODE command. The data extents that are already copied to the target replication server by storage pool protection operations are skipped when node replication is started.

As part of the PROTECT STGPOOL operation, processes might run to repair damaged extents in the target server's storage pool. The repair operation occurs under the following conditions:

Both the source server and the target server must be at V7.1.5 or later.
Extents that are already marked as damaged on the target server are repaired. The repair process does not run an audit process to identify damage.
Only target extents that match source extents are repaired. Target extents that are damaged but have no match on the source server are not repaired.

Limitations: The repair operation that runs as part of the PROTECT STGPOOL operation has the following limitations:

Extents that belong to objects that were encrypted are not repaired.
The timing of the occurrence of damage on the target storage pool and the sequence of REPLICATE NODE and PROTECT STGPOOL commands can affect whether the repair process is successful. Some extents that were stored in the target storage pool by a REPLICATE NODE command might not be repaired.

Privilege class

To issue this command, you must have system privilege.

Syntax


>>-PROTect STGPool--source_stgpool------------------------------>

   .-FORCEREConcile--=--No------.   
>--+----------------------------+------------------------------->
   '-FORCEREConcile--=--+-No--+-'   
                        '-Yes-'     

                        (1)                  
   .-MAXSESSions--=--10------------------.   
>--+-------------------------------------+---------------------->
   '-MAXSESSions--=----number_sessions---'   

   .-Preview--=--No------.  .-PURGEdata--=--No----------.   
>--+---------------------+--+---------------------------+------->
   '-Preview--=--+-No--+-'  '-PURGEdata--=--+-No------+-'   
                 '-Yes-'                    +-All-----+     
                                            '-Deleted-'     

   .-Wait--=--No------.  .-TRANSFERMethod--=--Tcpip---------.   
>--+------------------+--+----------------------------------+--><
   '-Wait--=--+-No--+-'  |                              (2) |   
              '-Yes-'    '-TRANSFERMethod--=--+-Tcpip-+-----'   
                                              '-Fasp--'

Notes:

If the TRANSFERMETHOD parameter is set to the default value of TCPIP, the default value of the MAXSESSIONS parameter is 10. If the TRANSFERMETHOD parameter is set to FASP, the default value of the MAXSESSIONS parameter is 2.
The TRANSFERMETHOD parameter is available only on Linux x86_64 operating systems.

Parameters

source_stgpool (Required)

Specifies the name of the directory-container storage pool on the source server.

Restriction: You must specify the PROTECTSTGPOOL parameter on the DEFINE STGPOOL or UPDATE STGPOOL command to back up the data.

FORCEREConcile

Specifies whether to reconcile the differences between data extents in the directory-container storage pool on the source server and target server. This parameter is optional. The default value is NO. Specify one of the following values:

No: Specifies that data backup does not compare all data extents in the directory-container storage pool on the source server with data extents on the target server. Instead, data backup tracks changes to the data extents on the source server since the last backup and synchronizes these changes on the target server.
Yes: Specifies that data backup compares all data extents on the source server with data extents on the target server and synchronizes the data extents on the target server with the source server.

MAXSESSions

Specifies the maximum allowable 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 2 - 100.

The default value varies:

If TRANSFERMETHOD=TCPIP, the default value of the MAXSESSIONS parameter is 10.
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 protection depends on the amount of data that is backed up. If you are backing up only a small amount of data, increasing the number of sessions provides no benefit.

Preview

Specifies whether to preview data. This parameter is optional. The default value is NO. Specify one of the following values:

No: Specifies that the data is backed up to the target server but that the data is not previewed.
Yes: Specifies that data is previewed but not backed up.

PURGEdata

Specifies that data extents are deleted from the target server. This parameter is optional. The default value is NO. You can specify one of the following values:

No: Specifies that data extents are not deleted from the target server.
All: Specifies that all data extents are deleted from the target server. Data extents that are referenced by other data in the target storage pool are not deleted.
Deleted: Specifies that data extents that were deleted on the source server are deleted from the target server. New data extents are not protected.

Wait

Specifies whether to wait for the server to process this command in the foreground. This parameter is optional. The default value is NO. You can specify one of the following values:

No: Specifies that the command is processed in the background. To monitor the background processes of this command, issue the QUERY PROCESS command.
Yes: Specifies that the command is processed in the foreground. Messages are not displayed until the command completes processing.
Restriction: You cannot specify WAIT=YES from the server console.

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 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.

Example: Delete all data extents from the target server

Delete all data extents in a directory-container storage pool on the target server. The directory-container storage pool that is named POOL1 on the source server is no longer protected by the directory-container storage pool on the target server. You might delete all extents to clean the directory-container storage pool on the target server that no longer protects the source server.

protect stgpool pool1 purgedata=all

Example: Protect a storage pool and specify a maximum number of data sessions

Protect a storage pool that is named SPOOL1 on the source server by backing up the data to a target replication server, TPOOL1. Specify a maximum of 20 data sessions.

update stgpool spool1 protectstgpool=tpool1
protect stgpool spool1 maxsessions=20

Table 1. Commands related to PROTECT STGPOOL
Command	Description
CANCEL PROCESS	Cancels a background server process.
DEFINE STGPOOL (directory-container)	Define a directory-container storage pool.
DEFINE STGPOOLDIRECTORY	Defines a storage pool directory to a directory-container or cloud-container storage pool.
REPAIR STGPOOL	Repairs a directory-container storage pool.
REPLICATE NODE	Replicates data in file spaces that belong to a client node.
SET REPLSERVER	Specifies a target replication server.