HP StorageWorks MSL2024, User'S And Service Manual

Page: 168 / 276

Connection from the host server to the disks
The connection between the host server and the disks determines how much data can be transferred
from the disks to the host computer at a time. A connection with insufficient bandwidth cannot provide
enough data for the tape drives to write at full speed. Find the performance impact of your system's
disk connection in
Table 40 .
Table 40 Performance impact of various disk connections
Recommendations Performance impact Connection type
For good performance, use a
faster connection with LTO-3,
LTO-4, and LTO-5 tape drives.
• LTO-2: GOOD . When fully used, a 1 Gb fibre
connection can provide enough bandwidth for
two LTO-2 tape drives.
• LTO-3, LTO-4, LTO-5: POOR . A 1 Gb fibre
connection is inadequate for an LTO-3, LTO-4,
or LTO-5 tape drive.
Fibre: 1 Gb
For good performance, use a
faster connection if you have
multiple LTO-3 or LTO-4 tape
drives, or an LTO-5 tape drive.
• LTO-2: GOOD . When fully used, a 2 Gb fibre
connection can provide enough bandwidth for
4 LTO-2 tape drives.
• LTO-3: GOOD . When fully used, a 2 Gb fibre
connection can provide enough bandwidth for
an LTO-3 tape drive.
• LTO-4 HH: GOOD . When fully used, a 2 Gb
fibre connection can provide enough bandwidth
for an LTO-4 HH tape drive.
• LTO-4 FH: NEUTRAL . A fully used 2 Gb fibre
connection can provide enough bandwidth for
many data sets but is not enough for 2:1 com-
pressible data.
• LTO-5: POOR . A 2 Gb fibre connection is inad-
equate for an LTO-5 tape drive.
Fibre: 2 Gb
GOOD . When fully used, a 4 Gb fibre connection
can provide enough bandwidth for the following
number of tape drives:
• LTO-2: 8
• LTO-3 HH: 4
• LTO-3 FH: 2
• LTO-4 HH: 2
• LTO-4 FH: 1
• LTO-5: 1
Fibre: 4 Gb
GOOD . When fully used, an 8 Gb fibre connection
can provide enough bandwidth for the following
number of tape drives:
• LTO-2: 16
• LTO-3 HH: 6
• LTO-3 FH: 5
• LTO-4 HH: 3
• LTO-4 FH: 2
• LTO-5: 2
Fibre: 8 Gb
Troubleshooting 168