NOTE:
Unlike most tape technologies, an LTO tape drive can write data as fast as the server
can send it, even if the tape drive is not streaming.
Find the performance impact of your system's Autoloader connection in
Table 31 Performance impact of various Autoloader connections
Recommendations
Performance impact
Connection type
Ultra 320 is an excellent transport medium,
but only has enough bandwidth for one
LTO-3 or LTO-4 drive per bus.
GOOD
. When fully used, an Ultra 320 SCSI
connection can provide enough bandwidth
for the following number of tape drives,
assuming 2:1 compression:
Parallel SCSI: Ultra 320
NOTE:
If the parallel SCSI cables are not
designed for Ultra 320 speeds or more than
a couple devices are on the parallel SCSI
bus, the bus may slow down to Ultra 160
speed.
•
LTO-2: 2
•
LTO-3, LTO-4: 1
Ultra 160 is a good transport medium, but
does not have enough bandwidth for LTO-3
Parallel SCSI: Ultra 160
•
LTO-2:
GOOD
. When fully used and
assuming that the connection to the disks
or LTO-4 tape drives. If using LTO-3 or
does not force the speed to a lower
LTO-4, upgrade to an Ultra 320 HBA,
parallel SCSI type, an Ultra 160
especially if you have greater than 2:1
compressible data.
connection can provide enough
bandwidth for two LTO-2 tape drives.
•
LTO-3:
MARGINAL
. An Ultra 160
connection is barely adequate for an
LTO-3 tape drive. The bus would be
saturated with 2:1 compressible data.
•
LTO-4:
POOR
. An LTO-4 tape drive is
unable to sustain maximum transfer
speeds with 2:1 compressible data.
Upgrade to Ultra 320.
Parallel SCSI: Ultra 2 (80)
•
LTO-2:
MARGINAL
. Ultra 2 (80) barely
has enough bandwidth for one LTO-2
drive.
•
LTO-3, LTO-4:
POOR
. An Ultra 2 (80)
connection is inadequate for an LTO-3
or LTO-4 tape drive.
Upgrade to Ultra 320.
Ultra Wide and Fast Wide are inadequate
for all of the currently supported tape drives.
Parallel SCSI: Ultra Wide,
Fast Wide
POOR
. One gigabit fibre is inadequate for
an LTO tape drive.
Fibre Channel: 1 Gb
•
LTO-5:
POOR
. Two gigabit fibre is
inadequate for an LTO-5 tape drive.
Fibre Channel: 2 Gb
GOOD
. When fully used, 4 Gb and 8 Gb
Fibre Channel have sufficient bandwidth for
all supported tape drives.
Fibre Channel: 4 Gb, 8 Gb
GOOD
. When fully used, 3 Gb and 6 Gb
SAS have sufficient bandwidth for all
supported tape drives.
SAS: 3 Gb, 6 Gb
Media
Once the data gets to the tape drive, it must be written onto the tape. If there are no bottlenecks
and the Autoloader starts having performance problems:
•
Try a new cartridge. A marginal cartridge can cause performance problems when the tape
drive has to retry writing to bad spots on the tape.
•
Clean the tape drive. See
for instructions.
Performance problems 103
Summary of Contents for BL536A
Page 149: ...German laser notice Italian laser notice Japanese laser notice Laser compliance notices 149 ...
Page 151: ...Danish notice Dutch notice Estonian notice Finnish notice French notice Recycling notices 151 ...
Page 155: ...French battery notice German battery notice Battery replacement notices 155 ...
Page 156: ...Italian battery notice Japanese battery notice 156 Regulatory compliance and safety ...