SCSI cable problem .
We need to connect one 3514-213, one 7208(5GBy) and one 9348 to two
machines simultaneously one RISC System 6000 Model 380 and
one Model 250.
We plan to use the devices from only one machine at the same time.
We plan to connect the 3514-213 using SCSI-2 F/W diff adapters
in each machine . With Y cables in each adapter in order to share
Our problem is we need to share the tapes too.
Is there some way to connect the tapes to the shared SCSI-2 F/W DIFF
interface without affecting the capability to share 3514?
If the answers is no, is there a way to share the tapes devices using
the integrated scsi units of both machines?
Could you tell me which cables are needed?
The 3514-213 is currently not supported in a twin-tailed environment.
The cabling for a twin-tailed 3514 configuration has not yet been
tested. The 3514-213 has not been tested in a multi-initiator
environment (HACMP or no HACMP), so the results of this
configuration are not predictable.
In theory, you can connect the 3514-213 as described, however, if
you run into problems, this twin-tailed configuration is not
supported by IBM.
In a non-twin-tailed environment, AIX will allow one system to
control the 3514-213 by importing and varyon the volume group.
This has not been tested in twin-tailed environment with the
3514-213, however, IN THEORY, it could work to allow one system
to control the device at a time. But again, this is not supported
by IBM currently.
It is NOT possible to connect the twin-tailed tape drives to the
integrated SCSI interfaces on the 250 and the 380. There are
several reasons for this:
o The 250 has an integrated SCSI-2 Fast/Narrow (8-bit) connector,
50-pin interface. This adapter does not support twin-tailing
because you cannot remove the adapter termination. In standard
twin-tailing configurations, you MUST remove adapter internal
SCSI termination because either the PTT or Y-Cables will provide
SCSI bus termination. PTT and Y-Cables have a termination point
built in. Thus, cabling the 8-bit Y-Cable (this cable has a
50-pin interface) to the 250 integrated SCSI-2 will at least
result in a "triply" terminated SCSI bus (not considering the
380's integrated adapter).
o More than 2 terminators on a SCSI bus will NOT work.
NOTE: The PTT Cables CANNOT be connected to the 250's integrated
SCSI-2 50-pin interface, because PTT cables have 60-pin
connectors. PTT cables are supported with the SCSI-1 SE and
SCSI-2 8-bit SE external Micro Channel adapters.
o The 380 has an integrated SCSI-2 F/W connector. This can
be cabled to have an 8-bit bus, however, this adapter does
not support twin-tailing. The internal termination cannot
be moved to an outside point. So, with the 250 integrated
controller and Y-cables, this configuration would result in a
4-times-terminated SCSI bus. This will NOT work.
o NOTE: PTT cables CANNOT be used on the 380's integrated
SCSI-2 F/W connector, even with the 8-bit converter.
o Twin-tailing on integrated SCSI adapters is not supported
because it WILL NOT WORK.
ISSUES ON SHARING TAPES DRIVES:
o IBM does not support twin-tailing these tape drives. The
integrated SCSI adapters on the 250 and 380 are not suitable
for twin-tailing any device. You would require EXTERNAL
SCSI-1 SE adapters (with no internal SCSI devices) and PTT
cables, OR Micro Channel SCSI-2 F/W 8-bit SE adapters and
8-bit Y-Cables to achieve a workable twin-tailed solution.
o No mixing PTT and Y-cables on the same bus.
o This solution is NOT supported or tested by IBM.
o AIX assumes that only one system owns a tape drive. AIX cannot
manage tape drives to intelligently handle concurrent attempts
to access the device. Tape drive access would have to be
monitored by a third party software or manually managed through
AIX commands (i.e. making the device "Available" to only one
system at a time).
o IBM does not provide or support SCSI switches that will permit
shared tape operation between two systems.
o You may wish to investigate the SYSBACK/6000 offering as a
possible supported solution. This offering will allow
customers to backup/restore data to/from a remote tape drive.
Only one system is attached to (or "owns") the tape drive.
For additional details about SYSBACK, please refer to the
SWAPPLIC application on HONE, product number 5764-047.
S e a r c h - k e y w o r d s:
SHARE TAPE SYSBACK 3514 TWIN-TAILING HIGH AVAILABILITY
WWQA: ITEM: RTA000069533 ITEM: RTA000069533
Dated: 06/1996 Category: ITSAI6000HW
This HTML file was generated 99/06/24~12:43:25
Comments or suggestions?