Control Path Drives; Mixed Drives - IBM TS4300 User Manual

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Table 7. Drive information and performance specification for half-height drives (continued)
Generation
Average rewind
time (REWIND
command)
Average rewind time (part of UNLOAD command, dependent on mount activity)
Less than 5 Gb
of contiguous data
transferred
5 Gb to 50 Gb
of contiguous data
transferred
All other types of
mount activity
1
By using the built-in data-compression capability of the tape drive, greater data rates than the native
data transfer rate are achieved. However, the actual throughput is a function of many components, such
as the host system processor, disk data rate, block size, data compression ratio, SAS bus capabilities,
and system or application software.
2
Cartridge initialization time can vary. See "Media optimization" on page 17 for more information.
3
See "Archive mode unthread" on page 18 for more information.
Remember:
• All sustained data rates depend on the capabilities of the interconnect.
• Drive performance varies with media generation and drive interface (SAS/FC).

Control path drives

A control path is a logical path to the library.
A control path is the path for SCSI Medium Changer commands that are sent by a server to control a
specific logical library. The library has no direct SCSI connection to a host server. When a software host
server communicates with the library, it sends the communication by way of a tape drive. The tape drive is
designated as a control path drive.

Mixed drives

All supported generations of LTO tape drives and cartridges can be in the same physical library and within
a single module.
This library supports a mixture of LTO drive types in a logical library. Some independent software vendors
(ISVs) support mixed drive types within a logical library and other do not. Some ISVs that support mixed
drive types might have restrictions. For details, contact your ISV.
Figure 13 on page 14 shows examples of methods for mixing LTO drive types in a logical library.
LTO 9 LTO 8
62 seconds 59 seconds
62 seconds 59 seconds
124 seconds 59 seconds
186 seconds 59 seconds
LTO 7 LTO 6
60 seconds NA
3
60 seconds NA
60 seconds NA
60 seconds NA
Chapter 1. Overview 13