Inventory times

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Various types of inventories are supported by the TS4500 tape library. 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 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 1 shows the typical time required for the tape library to inventory cartridges.
Table 1. Typical time required 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:
  • Power on the tape library
  • Issue the SCSI Initialize Element Status with Range command
  • Close the front door after manually accessing the inventory. Only those frames whose doors were opened are inventoried.
  • 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:
  • A Tier 1 cartridge bar code label has changed
  • Enough Tier 1 bar code labels have changed in a column to warrant an inventory of the entire column
  • Scan all tiers is selected when initiating a manual inventory from the TS4500 management GUI

Table 2 shows the typical time required for the tape library to inventory all tiers during a bulk load.

Table 2. Typical time required to inventory all tiers
Frame component Typical time to inventory all tiers (in seconds)
Full HD slot 15
Model L25/D25 column of full HD slots (0 - 5 per frame) 280
Model S24/S25 column of full HD slots (0 - 5 per frame) 415
Model L55/D55 column of full HD slots (0 - 5 per frame) 390
Model S54/S55 column of full HD slots (0 - 5 per frame) 580
Table 3 provides typical inventory times for several example frame configurations.
Table 3. Typical time required to inventory a frame for example frame configurations
Frame configuration* Typical time to inventory (in seconds)
No cartridges changed One tier 1 cartridge changed Initial bulk load
Model S55 in frame position 1 48 63 2344
Model D55 with 3 drive columns and no I/O stations in frame position 1 66 81 1602
Model L25 with 4 drive columns and 2 I/O stations in frame position 2 88 103 1458
Model S25 in frame position 2 60 75 2105
*Assumes that the frame is 99% full.