SUMMARY: Sparc 1+ disk drive configurations

From: Stewart Castaldi (stewartc@amc.com)
Date: Wed Jan 27 1993 - 04:04:30 CST


My original question:

> I need to submit a purchase order by the end of the week for 2G of
> disks to hang off of a Sparc 1+. I have noticed talk on the network
> of problems with the SCSI bus being very sensitive to length on the
> 1+'s. I also had one vendor say their 1.7G drive was known not
> to work on a 1+. Does anybody have a working system with 3-5 drives
> on it? How about with an SBUS Fast SCSI card? I would like to put
> 3 external 1G or greater drives on this machine. My configuration:
>
> Sparc 1+
> 2 - 105M Quantum internal drives
> SunOS 4.1.1 with >1G patch installed.

The consenus seems to be that there can be problems but they usually
can be avoided by using short cables, S-bus cards, and active terminators.
We have opted for a S-bus fast SCSI card with a 2G disk and an active
terminator.

Thanks to:

bossert@thalatta.com
vasey@issi.com
brian@zexel.com
soac.bellcore.com!cal
ekurgpol@develop-law.usc.edu
eptsun1.ctd.ornl.gov!ept
anasazi!jean
zeke@mpl.ucsd.edu
glenn%ups.uucp@fourx.Aus.Sun.COM
kevin%ups.uucp@fourx.Aus.Sun.COM
uunet!MELPN1.Prime.COM!GAM.GAR

Stewart Castaldi DNS: stewartc@amc.com
Applied Microsystems Corporation UUCP: uunet!amc-gw!stewartc
Redmond, Washington 98073 Dial: (206) 882-5326

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We've had problems putting any more than 3 external devices on a 1+
since Sun changed the OS to use synchronous SCSI for devices that support
it. The sync SCSI does improve I/O speed, but the timing tolerances
become much tighter and the cabling for external devices becomes a
significant issue.

Our configurations are similar to yours. Almost all of our Sparcstations
(including SS1, SS1+, IPC, SS2, and SS10) have 2 internal disks.
We have done several things to make life easier for ourselves when connecting
several external devices to our Sparcstations (we reconfigure a lot):

        1) double height shoeboxes eliminate feet of SCSI cabling

        2) SHORT SCSI CABLES! 2-3 feet max between boxes.

        3) SBUS SCSI cards when we want to attach something like 2 disks
           and 2 exabyte drives to a Sparcstation. We've bought the
           inexpensive (not fast) cards, and they work fine to attach
           a pair of Exabyte drives to. For disks, you may want to
           go with a fast SCSI card.

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 The max length the scsi buss can be on sparc is 6 meters.
 Apart from the cable lengths, you should also take into account
 the actual hardware attached to the scsi bus when calculating the
 length.

 Here is the lengths associated with different hardware items..

 Pizza box (CPU 1 1+ 2 IPC IPX etc etc ) .6 meter
 Lunch Box (Sony cdrom, 424MB desktop, etc etc ) .4 meter
 Dinner Box (1.3GB desktop, Exabyte desktop, etc etc) 1 meter
 ESM box ( Old style Sun peripheral box..) 1 meter
 Expansion cabinet 2.5 meter

 I know of one disk that works well on sparc 1 and 1+,
 Hitachi DSK16C-16 1.6GB unformated.
 It requires a minimum Sunos version of 4.1.1 and the 1GB patch.

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We have the fast SCSI boards, 9G worth of external disk
plus two exabyte tape drives per Sparc10 workstation.

We also had problems setting up what we needed. We have two
fast SCSI boards per workstation. On scsibus0, I have my
internal hard disk, sd1 (2G), sd2 (2G) and sx0 (exabyte
drive). This bus was giving me problems. The error message
was "transport failure: esp0 SCSI "reset", and continued
to spurt in the console window and drag all processes to a
halt. My vendor (Co Comp, Inc.) sent a 1.5 foot SCSI cable to
put in place of one of my 3 foot cables, and an "active" SCSI
terminator. This has made the difference. My machine had a
problem with 8 feet of SCSI chain. The other workstation didn't
choke until maybe 10 feet. The other workstation has actually
had no problem with 12 feet of SCSI chain, as long as the
terminator is active.

Your options are:
        add another SBUS to SCSI card
        limit the length of all external SCSI cables possible
        trim some of the ribbon cable inside the device cabinets
                (that'll get you maybe a foot)
        make sure your terminators are "active"

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> Does anybody have a working system with 3-5 drives on it?

We currently have SS1s and SS2s with 4 SCSI drives (2 internal, 2 external)
... and no problems. I have also set up SS1+s similarly for temporary
servers without incident, and am not aware that they are inherently more
sensitive to configuration variations (cable lengths, etc.) than the others.

The main thing is to keep your cable lengths reasonable and be aware of
the type and location of your SCSI bus terminations. Go for it!

> I would like to put 3 external 1G or greater drives on this machine.

If you want to use a GENERIC kernel and the internal SCSI bus, you'll need
to disconnect an internal drive just as well ... it doesn't add much).
Everything can be combined if you configure a custom kernel and retarget
of the tape drives to a disk name (so they tell me ... I like GENERICs ;^).

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We currently have the following drives off of our Sparc 1+:
   + 2 Fujitsu 1.2GB drives
   + 1 Seagate 1.6GB drive
   + 1 Sun 669MB drive

I doubt if we would buy a 1.6GB again, but will stick with
the 1.2GB FUjitsus's: we had considerable trouble finding
a reliable 1.6GB drive and have had virtually zero problems
with the 1.2GB's.

Also, if you have all of your data on one disk (i.e., a 2GB
drive) and that disk goes, then you are hosed. But if you have
your data spread around several disks, you can keep working even
if one disk goes.

And last, but not least, we have found that if you have a
networked environment, a heavily loaded system performs
faster if the disks are spread around the network: in short, this
is because if all disks are on one machine, then that one machine
does all of the disk reads and disk writes, whereas if the disks are
spread around the network, you have multiple machines performing
the reads and writes.

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I've got several 1+'s with 1 disk internal and 2 external disks plus
2 tapes *or* 1 tape+1 CDROM. everything works fine most of the time but
there is 1 unit that tends to act up more than any other .... hmmm. all my
systems are runnung 4.1.3. additionally, 2 1+'s each have a single drive
that is 1.3 GB formatted. all the fast-scsi stuff is on 2's or MP's.....

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My system is a SPARC 1, although I have heard that the SCSI buses on the two
systems have the same types of problems. My OS is 4.1.2 with no patches.

I recently purchased from Sun a 1.3 external hard drive, as well as a 5GB 8mm
tape drive. I also use their CDROM. I am using only the supplied cables,
which are about 2 feet long each. In addition to the external devices, I have
the two standard 105MB drives internal. I have had no problems in terms of
SCSI, and in fact my system is running better since I moved most of my stuff to
the new drive. The documentation for Sun's external expansion stuff has
information on how to calculate the distances for the SCSI cables, including
the cabling inside the boxes.

It seems to me that two or three Sun 1.3's would work, and I would imagine that
other vendor's disks would too. Just get *short* cables!

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Biggest recomendation - upgrade to 4.1.2 or 4.1.3 to take advantage of
the fast fsck. With 2G+ of disk you will be looking at 30 minute
reboots. The fast fsck in the newer releases will cut this back to less
than 5 minutes.

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I have 2 Fuji and one Maxtor on the same configuration. It will
be 4.1.3 next week, but the single most important factor was using
*very* short cables. Two of the disks are in a little PC cabinet
we bought, with a very short flat between them.

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don't have a 4/65, but suggest you talk to one of the VARs such
as R-Squared, Artecon, or Andataco. you should be able to get
a guarentee of function or money back (yes, I know that it's a
pain to send something back when you've invested time & sweat,
but this does give you an out).

R Squared 800 777 3478

Artecon 800 usa arte

Andataco 619 453 9191

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Give Steve Danbury @ MDL a call (861.6700)

We've bought lots of gear from him, he's very knowledgable about what
works with what, and he stands behind what he sells (peripherals).



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