Tivoli Storage Manager for Sun Solaris Administrator's Guide


Defining and Updating Device Classes for Sequential Media


Task Required Privilege Class
Define device classes System or unrestricted storage

You can define multiple device classes for each device type. For example, you may need to specify different attributes for two different storage pools that use the same type of tape drive. Variations may be required that are not specific to the device, but rather to how you want to use the device (for example, mount retention or mount limit).

If you are using device classes that have any of the following device types, you must define libraries and drives to the TSM server before you define device classes to access your sequential media:

See Chapter 6, Defining Drives and Libraries.

If you include the DEVCONFIG option in the dsmserv.opt file, the files you specify with that option are automatically updated with the results of this command. When you use this option, the files specified are automatically updated whenever a device class, library, or drive is defined, updated, or deleted.

The following sections explain the device classes for each supported device type.

Defining and Updating Device Classes for Tape Devices

To use tape devices, you must define a device class by issuing a DEFINE DEVCLASS command with the DEVTYPE parameter.

Note:For upgrades from Enhanced Version 2 to Version 3, you must define a device class with the DEVTYPE parameter set to DLT or ECART.


Device TSM Device Type
4mm 4MM
8mm 8MM
Digital linear tape DLT
Quarter-inch tape QIC
IBM 3570 3570
IBM 3590 3590
IBM 34xx CARTRIDGE
StorageTek tape devices ECARTRIDGE
Supported tape devices GENERICTAPE

Other parameters specify how to manage data storage operations involving the new device class:

You can update the device class by issuing the UPDATE DEVCLASS command.

Mount Limit

You can limit the number of drives that the device class has access to at one time with the MOUNTLIMIT parameter.

The default mount limit value is DRIVES. The DRIVES parameter indicates that every time a mount point is allocated, the number of drives online and defined to the library is used to calculate the true mount limit value. The maximum value for this parameter is 256 and the minimum value is 0. A zero value prevents new transactions from gaining access to the storage pool.

When selecting a mount limit for a device class, be sure to consider the following questions:

Mount Wait Period

The MOUNTWAIT parameter specifies the maximum amount of time, in minutes, that the server waits for a manual (or operator controlled) volume mount request to be satisfied before canceling the request. The default mount wait period is 60 minutes. The maximum value for this parameter is 9999 minutes.

Mount Retention Period

The MOUNTRETENTION parameter specifies the amount of time that a mounted volume should remain mounted after its last I/O activity. If this idle time limit is reached, the server dismounts the volume. The default mount retention period is 60 minutes. The maximum value for this parameter is 9999 minutes.

For example, if the mount retention value is 60, and a mounted volume remains idle for 60 minutes, then the server dismounts the volume.

If a volume is used frequently, you can improve performance by setting a longer mount retention period to avoid unnecessary mount and dismount operations.

If mount operations are being handled by manual, operator-assisted activities, you may want to use a large mount retention period. For example, if only one operator supports your entire operation on a weekend, then define a long mount retention period so that the operator is not being asked to mount volumes every few minutes.

While TSM has a volume mounted, the drive is allocated to TSM and cannot be used for anything else. If you need to free the drive for other uses, you can cancel TSM operations that are using the drive and then dismount the volume. For example, you can cancel server migration or backup operations. For information on how to cancel processes and dismount volumes, see Canceling Server Processes and Dismounting an Idle Volume.

Tape Label Prefix

By using the PREFIX parameter, you can specify a prefix value that is used to construct the file name string that is stored in the label area of each tape volume.

The prefix string is used as the prefix of the file name that is written to the label of each tape.

The default value for the tape label prefix string is ADSM.

Recording Format

You can use the FORMAT parameter to specify the recording format used by TSM when writing data to a tape. The following tables show the values supported for the tape device classes:

Device Class Reference
4MM Table 7
8MM Table 8
DLT Table 9
QIC Table 10
3570 Table 11
3590 Table 12
CARTRIDGE Table 13
ECARTRIDGE Table 14
GENERICTAPE Defining and Updating Device Classes for Generic Tape Devices

Use the FORMAT=DRIVE parameter only if all drives that can be accessed by the device class are identical. If some drives associated with a device class support a higher density format than others, mount errors can occur when you specify FORMAT=DRIVE.

The recording format that TSM uses for a given tape volume is selected when the first piece of data is written to the volume. Note that updating the FORMAT parameter of a device class does not affect tapes that already contain data until those tapes are rewritten from the beginning. This process may happen after a volume is reclaimed or deleted, or after all of the data on the volume expires.

Table 7. Recording Format and Default Estimated Capacity for 4mm Tape Volumes

Recording Format Estimated Capacity Description
DDS1 1.3GB (60-meter) 2.0GB (90-meter) Specifies that TSM writes data using the DDS-1 recording format, without compression. The result is a cartridge capacity of 1.3GB on 60-meter tapes and 2.0GB on 90-meter tapes. This format only applies to 60- and 90-meter tapes.
DDS1C 1.3GB (60-meter) 2.0GB (90-meter) Specifies that TSM writes data using the DDS-1 recording format, with compression enabled. The result is a cartridge capacity of approximately 1.3GB on a 60-meter tape, or 2.0GB on a 90-meter tape. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater, depending on the effectiveness of compression.
DDS2 4.0GB Specifies that TSM writes data using the DDS-2 recording format, without compression. The result is a cartridge capacity of 4.0GB on 120-meter tapes. This format only applies to 120-meter tapes.
DDS2C 8.0GB Specifies that TSM writes data using the DDS-2 recording format, with compression. The result is a cartridge capacity of 8.0GB on 120-meter tapes. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater, depending on the effectiveness of compression. This format only applies to 120-meter tapes.
DDS3 12.0GB Specifies that TSM writes data using the DDS-3 recording format, without compression. The result is a cartridge capacity of 12.0GB on 125-meter tapes. This format only applies to 125-meter tapes.
DDS3C 24.0GB Specifies that TSM writes data using the DDS-3 recording format, with compression. The result is a cartridge capacity of 24.0GB on 125-meter tapes. This format only applies to 125-meter tapes.
DDS4 20.0GB Specifies that TSM writes data using the DDS-4 recording format, without compression. The result is a cartridge capacity of 20.0GB on 150-meter tapes. This format only applies to 150-meter tapes.
DDS4C 40.0GB Specifies that TSM writes data using the DDS-4C recording format, with compression. The result is a cartridge capacity of 40.0GB on 150-meter tapes. This format only applies to 150-meter tapes.
DRIVE -- Lets the server select the recording format to use based on the drive on which the volume is mounted.

Table 8. Recording Format and Default Estimated Capacity for 8mm Tape Volumes

Recording Format Estimated Capacity Description
8200 2.3GB Specifies that TSM writes data using the 8200 recording format for standard 112-meter tape cartridges.
8200C 3.5GB Specifies that TSM writes data using the 8200C recording format for standard 112-meter tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 3.5GB, depending on the effectiveness of the compression feature.
8500 5.0GB Specifies that TSM writes data using the 8500 recording format for standard 112-meter tape cartridges.
8500C 7.0GB Specifies that TSM writes data using the 8500C recording format for standard 112-meter tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 7.0GB, depending on the effectiveness of the compression feature.
8900 20.0GB Specifies that TSM writes data using the 8900 recording format for standard 170-meter tape cartridges.
8900C 20.0GB Specifies that TSM writes data using the 8900C recording format for standard 170-meter tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 20.0GB, depending on the effectiveness of the compression feature.
AIT 25.0GB Specifies that TSM writes data using the AIT recording format on Sony AIT cartridges.
AITC 50.0GB Specifies that TSM writes data using the AITC recording format on Sony AIT cartridges. This format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 50.0GB, depending on the effectiveness of the compression feature.
DRIVE -- Lets the server select the recording format to use based on the drive on which the volume is mounted.

Table 9. Recording Format and Default Estimated Capacity for Digital Linear Tape Volumes

Recording Format Estimated Capacity Description
DLT10 10GB Specifies that TSM writes data using the DLT10 recording format on CompacTape III or CompacTape IV tape cartridges.
DLT10C 20GB Specifies that TSM writes data using the DLT10C recording format on CompacTape III or CompacTape IV tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 20GB, depending on the effectiveness of the compression feature.
DLT15 15GB Specifies that TSM writes data using the DLT15 recording format on CompacTape III XT tape cartridges.
Note:Use this format only with CompacTape III XT cartridges in a DLT2000XT, DLT4000, or DLT7000 tape drive.
DLT15C 30GB Specifies that TSM writes data using the DLT15C recording format on CompacTape III XT tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 30GB, depending on the effectiveness of the compression feature.
Note:Use this format only with CompacTape III XT cartridges in a DLT2000XT, DLT4000, or DLT7000 tape drive.
DLT20 20GB Specifies that TSM writes data using the DLT20 recording format on CompacTape IV tape cartridges.
Note:Use this format only with CompacTape IV cartridges in a DLT4000 or DLT7000 drive.
DLT20C 40GB Specifies that TSM writes data using the DLT20C recording format on CompacTape IV tape cartridges. However, this format uses the tape drive's hardware compression feature, and the actual capacity may be greater than 40GB, depending on the effectiveness of the compression feature.
Note:Use this format only with CompacTape IV cartridges in a DLT4000 or DLT7000 drive.
DLT35 35.0GB Specifies that TSM writes data using the DLT35 recording format on CompacTape IV tape cartridges.
Note:Use this format only with CompacTape IV cartridges in a DLT7000 drive.
DLT35C 70.0GB Specifies that TSM writes data using the DLT35C recording format on CompacTape IV tape cartridges.
Note:Use this format only with CompacTape IV cartridges in a DLT7000 drive.
DLT40 40GB Specifies that TSM writes data using the DLT40 recording format. This results in a tape capacity of approximately 40.0GB when using CompacTape IV cartridges.
Note:Use this format only with cartridges in a DLT8000 drive.
DLT40C 80GB Specifies that TSM writes data using the DLT40C recording format. This results in a tape capacity of approximately 80.0GB when using CompacTape IV cartridges. This format, however, uses the tape drive's hardware compression feature, so the actual capacity of the cartridge may be greater 80.0GB, depending on the effectiveness of compression feature.
Note:Use this format only with cartridges in a DLT8000 drive.
DRIVE -- Lets the server select the recording format to use based on the drive on which the volume is mounted.

Table 10. Recording Format and Default Estimated Capacity for QIC Tape Volumes

Recording Format Estimated Capacity Description
QIC120 26MB to 172MB Specifies that TSM writes data using the QIC120 recording format.
QIC150 31MB to 207MB Specifies that TSM writes data using the QIC150 recording format.
QIC525 65MB to 427MB Specifies that TSM writes data using the QIC525 recording format.
QIC1000 169MB to 1.1GB Specifies that TSM writes data using the QIC1000 recording format.
QIC2GB 2.0GB Specifies that TSM writes data using the QIC2GB recording format.
QIC2GBC 2.0GB to 4.0GB Specifies that TSM writes data using the QIC2GBC recording format.
QIC4GB 4.0GB Specifies that TSM writes data using the QIC4GB recording format.
QIC4GBC 4.0GB to 8.0GB Specifies that TSM writes data using the QIC4GBC recording format.
QIC12GB 12.0GB Specifies that TSM writes data using the QIC12GB recording format.
QIC12GBC 12.0GB to 24.0GB Specifies that TSM writes data using the QIC12GBC recording format.
QIC5010 13.0GB to 16.0GB Specifies that TSM writes data using the QIC5010 recording format. Actual capacity depends on the media used.
QIC5010C 26.0GB to 32.0GB Specifies that TSM writes data using the QIC5010C recording format. Actual capacity depends on the media used.
QIC25GB 25.0GB Specifies that TSM writes data using the QIC25GB recording format.
QIC25GBC 25.0GB to 50.0GB Specifies that TSM writes data using the QIC25GBC recording format.
QIC50GB 50GB Specifies that TSM writes data using the QIC50GB recording format. This format is specific to the Tandberg SLR100 drive.
QIC50GBC 50GB to 100GB Specifies that TSM writes data using the QIC50GBC recording format. This format is specific to the Tandberg SLR100 drive.
DRIVE -- Lets the server select the recording format to use based on the drive on which the volume is mounted.

Table 11. Recording Format and Default Estimated Capacity for 3570 Tape Volumes

Recording Format Estimated Capacity Description
3570B 5GB Specifies that TSM writes data using the basic (uncompressed) recording format.
3570C 5GB Specifies that TSM writes data using the compressed recording format. This format uses the tape drive's hardware compression feature, which may allow for greater capacity depending on the effectiveness of the compression.
DRIVE -- Lets the server select the highest recording format to be used based on the drive on which the volume is mounted.

Table 12. Recording Format and Default Estimated Capacity for 3590 Tape Volumes

Recording Format Estimated Capacity Description
3590B 10GB Specifies that TSM writes data using the basic (uncompressed) recording format.
3590C 10GB Specifies that TSM writes data using the compressed recording format. This format uses the tape drive's hardware compression feature, which may allow for greater capacity depending on the effectiveness of the compression.
DRIVE -- Lets the server select the highest recording format to be used based on the drive on which the volume is mounted.

Table 13. Recording Format and Default Estimated Capacity for Cartridge Tape Volumes

Recording Format Estimated Capacity Description
3480 180MB 18-track basic recording format
3480XF 180MB 18-track compacted recording format
3490B 360MB 36-track basic recording format
3490C 360MB 36-track compacted recording format
DRIVE -- Lets the server select the recording format to be used based on the drive on which the volume is mounted.

Table 14. Recording Format and Default Estimated Capacity for ECARTRIDGE Tape Volumes

Recording Format Estimated Capacity Description
18T 360MB 18-track basic recording format
18TC 360MB 18-track compacted recording format
36T 720MB 36-track extended recording format
36TC 720MB 36-track compacted recording format
SD3A 10GB Basic recording format for a 91-meter tape cartridge
SD3AC 10GB Compacted recording format for a 91-meter tape cartridge
SD3B 25GB Basic recording format for a 204-meter tape cartridge
SD3BC 25GB Compacted recording format for a 204-meter tape cartridge
SD3C 50GB Basic recording format for a 392-meter tape cartridge
SD3CC 50GB Compacted recording format for a 392-meter tape cartridge
9840 20GB Basic recording format for a 270-meter tape cartridge
9840C 80GB Compressed recording format for a 270-meter tape cartridge
DRIVE -- Lets the server select the recording format to be used based on the drive on which the volume is mounted.

Estimated Capacity Value

TSM estimates the capacity of the volumes in a storage pool based on the parameters assigned to the device class that is associated with the storage pool. The estimated capacity value is also used by TSM when making decisions about when to initiate a reclamation process for volumes in the storage pool. For more information on how TSM uses the estimated capacity value, see How TSM Fills Volumes.

You can either accept the default estimated capacity value for a given device class or explicitly specify an estimated capacity that you want the server to use instead of the default.

For tape device classes, the default values selected by the server depend on the recording format used to write data to the volume. These values are listed by device class in the following tables:

Device Class Reference
4MM Table 7
8MM Table 8
DLT Table 9
QIC Table 10
3570 Table 11
3590 Table 12
CARTRIDGE Table 13
ECARTRIDGE Table 14
GENERICTAPE Defining and Updating Device Classes for Generic Tape Devices

Library

Before the server can mount a volume, it must know which drives can be used to satisfy the mount request. This process is done by specifying the library when the device class is defined. The library must contain drives that can be used to mount the volume.

Note that only one library can be associated with a given device class. However, multiple device classes can reference the same library. Unless you are using the DRIVES value for MOUNTLIMIT, you must ensure that the numeric value of the mount limits of all device classes do not exceed the number of drives defined in the referenced library.

There is no default value for this parameter. It is required, and so must be specified when the device class is defined.

Note:If the library associated with this device class is EXTERNAL type, it is recommended that you explicitly specify the mount limit instead of using MOUNTLIMIT=DRIVES.

Defining and Updating Device Classes for Generic Tape Devices

To use tape devices that are supported by the native Solaris device drivers, you must define a device class whose device type is GENERICTAPE. Do this by issuing a DEFINE DEVCLASS command with the parameter DEVTYPE=GENERICTAPE.

When you specify the GENERICTAPE device type for a manual library that has more than one drive defined, ensure that the device types and recording formats of the drives are compatible. Because the devices are controlled by a device driver, the TSM server is not aware of the following:

Other parameters specify how to manage server storage operations involving the new device class:

You can update the device class information by issuing the UPDATE DEVCLASS command.

Library

The LIBRARY parameter for a GENERICTAPE device class is used as described in Library.

Mount Limit

The mount limit value for a GENERICTAPE device class is used as described in Mount Limit.

Mount Retention

The mount retention value for a GENERICTAPE device class is used as described in Mount Retention Period.

Estimated Capacity

You can specify an estimated capacity value of any volumes defined to a storage pool categorized by a GENERICTAPE device class.

The default ESTCAPACITY value for a volume in a GENERICTAPE device class is 1GB. Specify a capacity appropriate for your particular tape drive.

Mount Wait

The mount wait value for a GENERICTAPE device class is used as described in Mount Wait Period.

Defining and Updating Device Classes for Optical Devices

To use optical media, you must define a device class by issuing the DEFINE DEVCLASS command with a DEVTYPE parameter for one of the optical devices:

Parameter Description
OPTICAL 5.25-inch rewritable optical media
WORM 5.25-inch write-once optical media

Other parameters specify how to manage data storage operations involving the new device class:

You can update the device class information by issuing the UPDATE DEVCLASS command.

Library

The LIBRARY parameter for OPTICAL and WORM device classes is used as described in Library.

Mount Limit

The mount limit value for OPTICAL and WORM device classes is used as described in Mount Limit.

Mount Wait Period

The mount wait period for OPTICAL and WORM device classes is used as described in Mount Wait Period.

Mount Retention Period

The mount retention period for OPTICAL and WORM device classes is used as described in Mount Retention Period.

Estimated Capacity Value

TSM estimates the capacity of the volumes in a storage pool based on the parameters assigned to the device class that is associated with the storage pool. The estimated capacity value is used by TSM when making decisions about when to initiate a reclamation process for volumes in the storage pool. It is also used to generate storage pool and volume reports. As a volume is written and filled, the server determines the actual capacity of the volume and uses this instead of the estimated capacity.

You can either accept the default estimated capacity value for a given device class or explicitly specify an estimated capacity that you want the server to use instead of the default.

Recording Format

You can use the FORMAT parameter to specify the recording format used by TSM when writing data to an optical cartridge. The following values are supported for OPTICAL and WORM device classes (Table 15):

Table 15. Recording Format for OPTICAL and WORM Drives

Recording Format Description
650MB Used with optical cartridges whose capacity is 650MB.
1300MB Used with optical cartridges whose capacity is 1300MB.
2600MB Used with optical cartridges whose capacity is 2600MB.
5200MB Used with optical cartridges whose capacity is 5200MB.
DRIVE Allows the server to select the recording format to be used based on the capabilities of the drive used to access the optical disk.

Defining and Updating Device Classes for REMOVABLEFILE Devices

You must define a device class by issuing the DEFINE DEVCLASS command with the DEVTYPE=REMOVABLEFILE parameter. See Configuring Removable Media Devices for more information.

Other parameters specify how to manage storage operations involving the new device class:

You can update the device class information by issuing the UPDATE DEVCLASS command.

Library

The LIBRARY parameter for a REMOVABLEFILE device class is used as described in Library.

Mount Retention Period

The mount retention value for a REMOVABLEFILE device class is used as described in Mount Retention Period.

Mount Wait Period

The mount wait value for a REMOVABLEFILE device class is used as described in Mount Wait Period.

Defining and Updating FILE Device Classes

The FILE device type is used for special device classes whose storage volumes are not physical units, such as tape or optical cartridges, but simulated storage volumes. Data is written sequentially into standard files in the file system of the server machine. You can define this device class by issuing a DEFINE DEVCLASS command with the DEVTYPE=FILE parameter.

Note:Do not use raw partitions with a device class type of FILE.

Because each volume in a FILE device class is actually a file, a volume name is a fully qualified file name string.

When you define the FILE device class, you can supply the following parameters to manage server storage operations for the new device class:

You can update the device class information by issuing the UPDATE DEVCLASS command.

Mount Limit

The mount limit value for FILE device classes is used to restrict the number of mount points (volumes or files) that can be concurrently opened for access by server storage and retrieval operations. Any attempts to access more volumes than indicated by the mount limit causes the requester to wait. The default value is 1. The maximum value for this parameter is 256.

Note:The MOUNTLIMIT=DRIVES parameter is not valid for the FILE device class.

When selecting a mount limit for this device class, consider how many TSM processes you want to run at the same time.

TSM automatically cancels some processes to run other, higher priority processes. If the server is using all available mount points in a device class to complete higher priority processes, lower priority processes must wait until a mount point becomes available. For example, TSM cancels the process for a client backup if the mount point being used is needed for a server migration or reclamation process. TSM cancels a reclamation process if the mount point being used is needed for a client restore operation.

Also consider the resources available on the target server when setting mount limits. Do not set a high mount limit value if the target cannot move enough data or access enough data to satisfy all of the requests.

If processes are often cancelled by other processes, consider whether you can make more mount points available for TSM use. Otherwise, review your scheduling of operations to reduce the contention for resources.

Maximum Capacity Value

You can specify a maximum capacity value that restricts the size of volumes (that is, files) associated with a FILE device class. Use the MAXCAPACITY parameter of the DEFINE DEVCLASS command. When the server detects that a volume has reached a size equal to the maximum capacity, it treats the volume as full and stores any new data on a different volume.

The default MAXCAPACITY value for a FILE device class is 4MB.

Directory

You can specify the directory location of the files used in the FILES device class. The default is the current working directory of the server at the time the command is issued, unless the DSMSERV_DIR environment variable is set. For more information on setting the environment variable, refer to Quick Start.

The directory name identifies the location where the server places the files that represent storage volumes for this device class. While processing the command, the server expands the specified directory name into its fully qualified form, starting from the root directory.

Later, if the server needs to allocate a scratch volume, it creates a new file in this directory. The following lists the file name extension created by the server for scratch volumes depending on the type of data that is stored.

For scratch volumes used to store this data: The file extension is:
Client data .BFS
Export .EXP
Database backup .DBB
Dump .DMP

Defining and Updating SERVER Device Classes

The SERVER device type is used for special device classes whose storage volumes are not directly attached to this server. A volume with device type SERVER consists of one or more files archived in the server storage of another server, called a target server. You can define this device class by issuing a DEFINE DEVCLASS command with the DEVTYPE=SERVER parameter. For information about how to use a SERVER device class, see Using Virtual Volumes to Store Data on Another Server.

Other parameters specify how to manage data storage operations for the new device class:

You can update the device class information by issuing the UPDATE DEVCLASS command.

Server Name

The TSM server on which you define a SERVER device class is called a source server. The source server uses the SERVER device class to store data on another TSM server, called a target server.

When defining a SERVER device class, specify the name of the target server. The target server must already be defined by using the DEFINE SERVER command. See Using Virtual Volumes to Store Data on Another Server for more information.

Mount Limit

Use the mount limit value for SERVER device classes to restrict the number of simultaneous sessions between the source server and the target server. Any attempts to access more sessions than indicated by the mount limit causes the requester to wait. The default mount limit value is 1. The maximum value for this parameter is 256.

Note:The MOUNTLIMIT=DRIVES parameter is not valid for the SERVER device class.

When selecting a mount limit, consider your network load balancing and how many TSM processes you want to run at the same time.

TSM automatically cancels some processes to run other, higher priority processes. If the server is using all available sessions in a device class to complete higher priority processes, lower priority processes must wait until a session becomes available. For example, TSM cancels the process for a client backup if a session is needed for a server migration or reclamation process. TSM cancels a reclamation process if the session being used is needed for a client restore operation.

If processes are often cancelled by other processes, consider whether you can make more sessions available for TSM use. Otherwise, review your scheduling of operations to reduce the contention for network resources.

Maximum Capacity Value

You can specify a maximum capacity value that restricts the size of files that are created on the target server to store data for the source server. The default MAXCAPACITY value is 500MB. The storage pool volumes of this device type are explicitly set to full when the volume is closed and dismounted.

Mount Retention

You can specify the amount of time, in minutes, to retain an idle sequential access volume before dismounting it. The default value is 60. The maximum value you can specify for this parameter is 9999. This parameter can improve response time for sequential access media mounts by leaving previously mounted volumes online.

Prefix

You can specify a prefix that the source server will use as the beginning portion of the high-level archive file name on the target server.

Retry Period

You can specify a retry period for communications with the target server. When there is a communications failure, this period determines the amount of time during which the source server continues to attempt to connect to the target server.

Retry Interval

You can specify how often the source server tries to connect to the target server when there is a communications failure. During the retry period, the source server tries to connect again as often as indicated by the retry interval.


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