Backup Applications And Target Libraries; Why Make Target Libraries Visible; Fan In, Fan Out And Job Concurrency Rules - HP StorageWorks D2D - Backup Systems User Manual

• An HP D2D 400x Target Appliance can run eight incoming replication jobs concurrently; a Source
Appliance can run four outgoing replication jobs.
• An HP D2D 41xx Target Appliance can run 16 incoming replication jobs concurrently; a Source
Appliance can run four outgoing replication jobs.
Table 4 Fan In, Fan Out and job concurrency rules
Appliance Fan Out
Appliance Fan In
Library Fan Out
Library Fan In
Concurrent target
jobs
Concurrent source
jobs

Backup applications and target libraries

Replication Target libraries are not normally visible to the host, but you can configure devices to make
them visible to backup applications. It allows the backup application to:
• Move cartridges from storage slots to drives in the library
• Perform SCSI commands on the library device
• Perform read and verify operations on the cartridge (but not write)
• Perform load/unload operations on the tape device
WARNING!
This facility should be used with care. If the backup application can see both source and target libraries,
it will not be able to distinguish between the source library and the target library because the barcodes
are duplicated in the two locations.

Why make target libraries visible?

There are two occasions when it may be useful to make a target library visible to the backup application
on the host.
• To confirm that replication is working correctly and check the integrity of the replicated backup
by doing a test restore
82 Configuring and using replication
Maximum number of Target appliances
supported by one Source appliance
Maximum number of Source appliances
supported by one Target appliance
Maximum number of Target libraries to
which a Source library may be mapped
Maximum number of Source libraries to
which a Target library may be mapped
Maximum number of concurrent incoming
replication jobs
Maximum number of concurrent outgoing
replication jobs
HP D2D
HP D2D 250x
400x
All: 2 4
D2D2502: 4
nl
D2D2503: 6
16
nl
D2D2504: 8
nl
nl
All: 1 1
All: 1 4
D2D2502: 2
nl
D2D2503: 3
8
nl
D2D2504: 4
nl
D2D2502: 1
nl
D2D2503: 1 4
nl
D2D2504: 2
HP D2D
41xx
4
24
1
4
16
4