IBM TS4500, Introduction And Planning Manual

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Some of the specific assumptions may not pertain to a given operating
environment. Actual performance may vary. Accordingly, the performance
information for this product does not constitute a performance guarantee or
warranty. Verify that the performance of the library is acceptable in your specific
environment.
The sections that follow describe the library's performance.
Inventory times
Various types of inventories are supported by the TS4500 tape library and the
amount of time required to create the inventory for the library or a frame in the
library varies with each type of inventory.
The TS4500 tape library tracks the logical location of all of its elements by
performing an automatic inventory as required. The automatic inventory improves
application performance. You can also manually initiate an inventory, if necessary,
from the System page of the TS4500 management GUI.
Table 27 shows the typical time required for the TS4500 tape library to inventory
cartridges.
Table 27. Typical time required for the TS4500 tape library to inventory cartridges
Frame Component Typical Time to Inventory in Seconds
Storage column (8 or 10 per frame) 6
Drive column (0-4 per frame) 6
I/O Station (0 or 2 per frame) 8
An inventory operation includes a check to determine whether each cartridge
storage slot in the library is empty or full, and a scan of the bar code labels. An
inventory occurs whenever you:
v
Power on the TS4500 tape library
v
Issue the SCSI Initialize Element Status with Range command
v
Close the front door after manually accessing the inventory
Note: When the library performs an automatic inventory because the front door
was closed, the inventory occurs only for those frames whose doors have been
opened.
v
Initiate an inventory from the TS4500 management GUI
Inventory all tiers
A standard inventory is a scan of Tier 0 and Tier 1, however at times it is necessary
to inventory all tiers. This operation takes more time because it requires moving
the cartridges to scan each bar code. For all inventory operations, tiers 2 and
higher are only scanned when one of the following changes occurs:
v
A Tier 1 cartridge bar code label has changed
v
Enough Tier 1 bar code labels have changed in a column to warrant an
inventory of the entire column
v
"Scan all tiers" is selected when initiating a manual inventory from the TS4500
management GUI
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IBM TS4500: Introduction and Planning Guide