Exabyte 2.2 Gb Streamer for ISC

[John Mcmillan]

In article <303 at sherpa.UUCP> guest at sherpa.UUCP (Guest Account) writes:
>In article <1990Aug01.125704.4279 at maxed>, root at maxed (0000-Admin(0000)) writes:
>>Has anyone been using an Exabyte (or related drive)?  How fast is
>>it?  Does it require special utilities or will tar or cpio
>>drive it with No Problem through a specific device (and what device
>>is that?)  HELP!
>
>I installed a 2.2G tape drive and a 720M hard drive in a system about 6 months
>ago.  The hard drive works great!!!  The tape drive STINKS!  Sorry to be so
>harsh, but the tape drive needs turned on and off 2 to 4 times per week!  This
>makes it very unreliable for unattended backups.  Now, the company that we
>purchased the tape drive from is NOT Exabyte, but I will bet money that it is
>the same drive.  Features and looks are what I base this on.  The place where
>we bought the drive from says that there is a known static problem with the
>drive, in other words, it is overly sensitive to static.
>
>The Exabyte drive might be fine, but just ask around about any unusual static
>problems with it, just to be sure.  I hate to see people get burned!
:

For 7 months I've been working with 3 3B2's SHARING 2 Differential SCSI busses,
and having an additional Single-Ended SCSI bus per machine.  This included two
Exabyte [Feith Systems packaged] tapes, an [almost unused]AT&T 9-track, and
7 disk controllers on the Diff' bus.  (Additionally, there was one Disk
controller and one Cartridge-tape contrller on each internal S-E SCSI.)

These tapes ran about 15 hours/day, but saw only about two tapes per day.
Typical throughput:
	find ... -print | cpio -oacC 32768 > ...    yielded about 300 MB/hr.
Much of our time was spent on remote, RFS'd File-systems at only about
120 MB/hr... not the tape's fault.  (Even the 300 MB/hr is presumably
below the tape's capabilities.)

Initially, Exabytes were on the Diff' SCSI and we had aggravatingly
frequent problems.  Turning the Exabyte drives off and on was a frequent
requirement -- once to a dozen times a week.  Service calls on them was
frequent -- about every month there was a call on one or the other
drive.  We've shipped drives for remote-service with cassettes
still in them because NOTHING would release the tapes!

Concerned about problems during booting and problems in which the
SCSI busses seemed to hang because of tape problems, we converted the
tapes to S-E SCSI and hung them off the internal busses.  Since then,
we've had fewer service calls and only replaced one.  Our inexplicable,
hair pulling reboot problems have about disappeared -- but... we've
made other improvements too, including isolating the almost unused 9-track.
But most significantly, we've stopped locking up the shared Diff' busses.

Exabyte's have been an unpleasant experience... but we've ordered another one
because where else can you get the volume of backup?  [Yeah... we thought
a lot about a stack of DAT's.  Have DAT's developed any track record yet?]


john mcmillan -- jcm at pegasus.att.com -- muttering for SELF ONLY, not AT&T