Tape spanning is possible, but not recommended. It is desirable to create cartridges with a size
greater than a full backup, so that the backup fits on one cartridge. However, cartridge formats
and sizes are present mainly to assist the user in identification within a backup application and
for offloading to physical tape. They have no impact on the amount of disk space allocated or
used by the StoreOnce Backup System, which is depends solely on the amount of user data backed
up. No additional disk space is used by creating larger size cartridges.
Limitations on the number of devices
An important consideration when configuring VTL devices is that the library and each drive that
you configure for it counts as a separate device. There are practical limitations on the number of
devices that each host and FC switch or HBA can access.
IMPORTANT:
The maximum number of devices per appliance also impacts on the number of
NAS shares that you can configure. For example: if you configure 250 devices on the HP D2D4312
or D2D4324, you will not be able to configure NAS shares. See also
Flexible emulation (page 13)
.
Table 3 Maximum number of libraries and drives per G3 B6000 appliance
with maximum couplets (4)
per node (couplet)
384
48 (96)
Max libraries
1536
192 (384)
Max drives per library
1920
240 (480)
Max devices per appliance node
16384
16384
Max slots per library (D2DBS)
G2 and G1 products:
For iSCSI VTL devices a single Windows or Linux host can only access a
maximum of 64 devices. A single library with 63 drives is the most that a single host can access.
Configuring a single library with more than 63 drives will result in not all devices in the library
being seen (which may include the library device). The same limitation could be hit with multiple
libraries and fewer drives per library.
Table 4 Maximum number of libraries and drives per G2 appliance
HP D2D4324
HP D2D4312
HP D2D4112
HP D2D4106
HP D2D2504i
HP D2D2502i
50
50
24
16
8
4
Max libraries
200
200
96
64
32
16
Max drives per
library
250
250
120
80
40
20
Max devices
per appliance
4096
4096
1024
1024
96
96
Max slots per
library
(D2DBS)
NOTE:
Apart from the HP D2D2502i, it is possible to exceed the maximum physical limitation
when configuring any of the above models.
12
Virtual Tape Devices
