Find the performance impact of your system's Autoloader connection in Table 31
Table 31 Performance impact of various Autoloader connections
RecommendationsPerformance impactConnection type
Ultra 320 is an excellent transport
medium, but only has enough bandwidth
for one LTO-3 or LTO-4 drive per bus.
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.
GOOD. When fully used, an Ultra 320
SCSI connection can provide enough
bandwidth for the following number of
tape drives, assuming 2:1 compression:
• LTO-2: 2
• LTO-3, LTO-4: 1
Parallel SCSI: Ultra 320
Ultra 160 is a good transport medium,
but does not have enough bandwidth
for LTO-3 or LTO-4 tape drives. If using
LTO-3 or LTO-4, upgrade to an Ultra
320 HBA, especially if you have greater
than 2:1 compressible data.
• LTO-2: GOOD. When fully used and
assuming that the connection to the
disks does not force the speed to a
lower parallel SCSI type, an Ultra
160 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.
Parallel SCSI: Ultra 160
Upgrade to Ultra 320.
• 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.
Parallel SCSI: Ultra 2
(80)
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
Troubleshooting126
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