Exabyte 221L, Руководство по эксплуатации продукта

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18
P
RODUCT
M
ANUAL
1014258
C
HAPTER
2—I
NSTALLING THE
L
IBRARY
C
ONNECTING THE
L
IBRARY TO
SCSI (221L)
This section provides guidelines for connecting the library to host systems via
SCSI. The 221L library and its tape drive(s) have independent wide LVD
(low-voltage differential) SCSI interfaces and can be connected to a single or
separate SCSI buses.
Note: To ensure optimum tape drive performance, connect the tape drive to an
Ultra3 (Ultra160) SCSI host bus adapter.
G
UIDELINES FOR
C
ONNECTING TO
SCSI
Before connecting the library and its tape drive(s) to SCSI, determine how
many SCSI buses you will be using, which bus will connect to which device,
and how many cables and terminators you will require. Keep in mind these
guidelines as you plan your SCSI connections:
For best performance, avoid connecting more than two LTO tape drives to
the same SCSI bus. You can connect a library with two LTO tape drives to a
single SCSI bus, but avoid placing additional LTO tape drives, whether
standalone or in other libraries, on the same SCSI bus.
Do not connect single-ended SCSI devices. Although single-ended SCSI is
compatible with LVD Ultra2 and Ultra3 (Ultra160) SCSI, Exabyte does not
support single-ended devices on the SCSI buses attached to the library or its
tape drive(s).
Do not connect the library to a RAID controller. The library will not operate
if it is connected to a RAID controller.
Do not exceed SCSI bus length restrictions. The maximum allowable length
of an LVD SCSI bus is 12 meters (39 feet) if you have more than two devices
on the bus. Make sure none of the buses attached to the library or its tape
drive(s) exceed this length. To determine the length of each bus:
a.
a. a.
a. Add together the lengths of all external SCSI cables on the bus.
b.
b. b.
b. For each bus attached to a tape drive, add 23 centimeters (9 inches) for
the internal cable length used by each tape drive on the bus.
c. c. c. c. For the bus attached to the library, add 5 centimeters (2 inches) for the
internal cable length used by the library.
d.
d. d.
d. Add the internal cable lengths for any other SCSI devices on the bus.
Make sure each SCSI bus is properly terminated. You must install a
terminator on the device at the physical end of each bus. Typically, one of the
library’s tape drives will terminate the bus. See page 11 for terminator
requirements.