Performance Impact Of Various Autoloader Connections - HP StorageWorks 1/8 User's And Service Manual

Find the performance impact of your system's Autoloader connection in
Table 31 Performance impact of various Autoloader connections
Connection type
Parallel SCSI: Ultra 320
Parallel SCSI: Ultra 160
Parallel SCSI: Ultra 2
(80)
Parallel SCSI: Ultra
Wide, Fast Wide
Fibre Channel: 1 Gb
Fibre Channel: 2 Gb
Fibre Channel: 4 Gb, 8
Gb
SAS: 3 Gb, 6 Gb
126 Troubleshooting
Performance impact
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
• 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.
• 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.
Ultra Wide and Fast Wide are
inadequate for all of the currently
supported tape drives.
POOR. One gigabit fibre is inadequate
for an LTO tape drive.
• LTO-5: POOR. Two gigabit fibre is
inadequate for an LTO-5 tape drive.
GOOD. When fully used, 4 Gb and 8
Gb Fibre Channel have sufficient
bandwidth for all supported tape drives.
GOOD. When fully used, 3 Gb and 6
Gb SAS have sufficient bandwidth for
all supported tape drives.
Table 31
Recommendations
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.
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.
Upgrade to Ultra 320.
Upgrade to Ultra 320.