SUMMARY: grinding disks

A. very good suggestions, thanks T.

My guess is that the SCSI command data flowing to and the raw data flowing
from
the tape drive is big enough and constant enough to cause gaps in the data
stream
to the disk drive. I suspect that the disk is constantly resetting the heads
to a
home location due to extended timing outages or actual interference from the
SCSI
command strings targetting the tape drive operations.

My assumptions made here are that you already have the 6 internal bays
inside the
E250 full of disk and you do not have another external SCSI channel
available on
this machine apart from the built in SE Wide SCSI connector on the back.

My recommendation would be to add a Dual SE SCSI card to the machine in one
of the
PCI slots and attach the multipack to the new controller, leaving the
DLT8000 on
the old channel. This would isolate any SCSI command activity for each
device to
its own path and keep the predominant flow of data going in the same
direction for
each device. If it is not possible to add a card, I would then change the
target
drive to one of the internal bays. As you are booting from CD, this should
just be
a matter of popping a drive from the multipack and temporarily exchanging it
for a
drive in an internal bay.

-----Original Message-----

OS=solaris 2.6
hardware=E250-->multipack-->dlt8000

problem: boot cdrom -s, mount /dev/dsk/c1t9d0s0 /a, ufsrestore -xvf
/dev/rmt/0n...
caused this and c1t8d0s0 9GB disks to grind and pull, causing an audible
popping sound throughout most of the restore.

after the restore is complete, the disk is quiet, fsck is quiet, newfs is
quiet, dd is quiet, only ufsrestore from the cdrom to the disk is loud.

what can explain this...bad multipack backplane, faster dlt????

your thoughts are appreciated.

rf




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