IBM System Storage TS3500, Introduction And Planning Manual

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The typical time required for the TS3500 Tape Library to audit cartridges is less
than 30 seconds per full HD slot. The typical time required for the TS3500 Tape
Library to audit a column of full HD slots in a Model S54 frame is less than 10
minutes and in a Model S24 frame is less than 8 minutes. If the inventory with
audit includes column 9 of an HD frame at the end of a library string, the
inventory could take an additional 3 to 6 minutes.
Mount performance and cartridge move time
This section describes mount performance and cartridge move times for the TS3500
Tape Library.
Mounts per hour is a measure of the overall capability of the cartridge accessor
and tape drives. It is defined as the number of cartridges that the TS3500 Tape
Library can mount in one hour. A mount, often called the demount and mount
cycle, involves the following steps: (1) removing the cartridge from a drive; (2)
returning it to a storage slot; (3) collecting another cartridge from a random storage
slot; (4) moving it to the drive; and (5) loading the cartridge into the drive.
Move time is the time required for the cartridge accessor to pick a cartridge from a
random slot, move the cartridge to a drive, pivot (if required), and insert the
cartridge into the drive.
Table 25 shows the mount performance and average move time for a TS3500 Tape
Library without dual accessors and without HD frames.
Table 25. Mount performance and move time for drives in a TS3500 Tape Library without dual accessors and without
HD frames
Library
Configuration
Drives in Frame 1 Drives in Center Frame
Mounts Per Hour
Average Move Time
in Seconds
Mounts Per Hour
Average Move Time
in Seconds
1 frame 550 2.7 N/A N/A
2 frames 520 2.6 N/A N/A
4 frames 410 3.3 430 2.9
6 frames 350 3.8 380 3.3
8 frames 310 4.4 350 3.7
12 frames 255 5.3 300 4.3
16 frames 215 6.2 260 4.7
Specifications were produced from models, but are consistent with test results.
Table 26 shows the mount performance for a TS3500 Tape Library with dual
accessors but without HD frames.
Table 26. Mount performance for drives in a TS3500 Tape Library with dual accessors but without HD frames
Library Configuration
(Active Frames
1
)
Mounts Per Hour
2
4 frames 1000
6 frames 900
8 frames 800
12 frames 700
16 frames 600
Chapter 1. Introduction
85