HP StorageWorks 1/8 - Page 121

RecommendationsPerformance impactConnection type
GOOD. When fully used, an 6 Gb
high-performance RAID array can support up to the
following number of tape drives:
• LTO-2: 20
• LTO-3, LTO-4: 12
• LTO-5: 2
SAS: 6 Gb
If cables not designed for Ultra
320 speeds are used or there are
more than a couple devices on the
bus, the bus may slow down to
Ultra 160 speeds.
• 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
320 connection can provide enough bandwidth
for five LTO-2 tape drives.
• LTO-3, LTO-4: 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 320 connection ban provide
enough bandwidth for a single LTO-3 or LTO-4
tape drive.
• LTO-5: POOR. An Ultra 320 connection is inad-
equate for an LTO-5 tape drive.
Parallel SCSI: Ultra
320
Upgrade to Ultra 320 for parallel
SCSI disk drives when using an
LTO-3 or LTO-4 tape drive,
especially if your data is greater
than 2:1 compressible.
• 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 when providing 2:1
compressible data to an LTO-3 tape drive.
• LTO-4 HH: MARGINAL. An Ultra 160 connec-
tion is barely adequate for an LTO-4 HH tape
drive. The bus would be saturated when
providing 2:1 compressible data to an LTO-4
HH tape drive.
• LTO-5: POOR. An Ultra 160 connection is inad-
equate for an LTO-5 tape drive.
Parallel SCSI: Ultra
160
Upgrade to Ultra 320 for parallel
SCSI disk drives when using an
LTO-3 or LTO-4 tape drive.
• LTO-2: MARGINAL. When fully used and assum-
ing that the connection to the disks does not
force the speed to a lower parallel SCSI type,
an Ultra 2 (80) connection barely provides
enough bandwidth for an LTO-2 tape drive.
• LTO-3, LTO-4, LTO-5: POOR. An Ultra 2(80)
connection is inadequate for an LTO-3, LTO-4,
or LTO-5 tape drive.
Parallel SCSI: Ultra
2 (80)
Upgrade to a faster transport
medium, such as Ultra 320 SCSI.
POOR. Ultra Wide and Fast Wide are inadequate
transport mechanism for LTO tape drives.
Parallel SCSI: Ultra
Wide, Fast Wide
HP StorageWorks 1/8 G2 Tape Autoloader User and service guide 121