SUMMARY: DDS Drives and Stackers- Misc Ramblings

From: Craig L. Gruneberg (
Date: Mon Feb 24 1997 - 13:17:06 CST

I posed the following query to the group longer ago than I care to

Original Plea for Help:

  Subject: 4mm Stackers

  Looks like it is time to update the archives on this one.

  Can anyone pass along their success/horror stories on 4mm stackers
  under Solaris 2.X ( preferably newer Solaris like 2.5 ).

  I want to buy a stacker but the only feedback I have got ( and it was
  all positive ) was on SUNs 4 tape unit. I was hoping to find a
  reliable stacker in the 5-8 tape category.

  Thanks and summary will follow but promptness is not guaranteed :-(


  I got alot of interesting comments- some having great luck with stackers
  and some not. Based on the answers I decided to go with a single tape
  DDS3 drive since the mechanicals on the stackers scare me.

  Thanks to all for taking the time to write. I've included all replies
  since there is some useful info in each.

From: Troy Wollenslegel <>

  I think we are using a Compaq 12 tape stacker. (Archive tape drive I
  think) It appears to work. Not my department, so I don;'t know much more
  than that.

From: Bernd Weninger - FFOS 16 <>

  There is a 4mm DDS-3 Stacker from Sun with 7 Slots, 72-144 GB, available
  now in an Internal version, the External version (which i ordered)
  lurking around the corner.

I asked Bernd if he had info on the external DDS3 7 tape SUN stacker:

From: Bernd Weninger - FFOS 16 <>

  Sorry, not of the External Version. I only have:
  Miscellaneous sale DDS3 4mm 72-144 GB.

  The Internal Version is:
  6293A 72-144GB 4mm DDS-3 Tape Auto-Loader for E5000 & E 6000 $8500
  6292A Same, but for expansion Rack $ 6000

From: Ric Anderson <>

  I've been using the HP C1553A stacker under solaris 2.5 with no problem.
  If you want to "random access" it, you need media changer software from
  Advanced Networking Technologies ( or

  This unit holds a 6 tape magazine, and is an "8Gb/tape" unit (i.e.,
  it uses 120m 4mm tapes, and you can get 8gb on those if your data
  is real compressable; I get about 1.6 compression on my stuff).

From: "Rick von Richter" <>

  We have two 4X stackers in our 2000 and man are they finicky (sp?). On
  the average, I have to have sun come out and replace either of these
  drives once a month because something always happens. One thing I
  found out; after you have inserted a tape and it starts to load, DO NOT
  hit any other buttons until it is done loading the tape. If you do hit
  a button, like you changed your mind or something and hit eject before
  it was done loading, it will freeze up immediately and go into a 'I
  don't know what the hell to do now' state.

From: Mark Bergman <>

  We're using a 12 tape 4mm DDS-II stacker (HP drive, ADIC stacker) VAR'ed
  by Boxhill Systems. All in all, I wouldn't buy it again. We've been
  through 4 units in the past 2 1/2 years (all replaced under the
  service contract). The last unit has performed flawlessly for ~6
  months, but overall I'm not happy.

  When it works, it's fine. ~4GB/cartridge.

  If I was buying a new unit, I might wait for the DDS-3 drives, or
  get a DLT drive. They are faster and have higher capacity, but cost
  more and the media is much more expensive.

From: bf566z9@is000913.BELL-ATL.COM (Kuldell)

  We have had mixed luck with them. Hardly ever a problem for ufsdumps
  of our filesystems, which have never taken more than 2 tapes.

  Frequent difficulties for database backups, but our databases
  run 80GB and more. We've run into problems writing the end of
  tape mark, locking the tape drive (necessitating a power cycle
  to the tape drive--and the whole server if you don't like taking
  apart the server when it's running).
  We've brought Box Hill in to give us a solution with SQL BackTrack,
  Legato NetWorker, and DLT tape drives.

From: Garry Robbins <>

  We've got about a dozen SUN 4mm DAT drives. Very few problems
  over the past four years. We use Networker (Legato and SUN flavours)
  to drive them.
  Depending on what your backup tool is,
  couldn't you put multiple 4mm DAT drives on the
  same node? Then you'd have up to 8 tapes... or 12, etc.

From: Dave Mitchell <>

  Slightly at a tangent this, so ignore me if you want, but ...
  Now that sun have brought out a DDS-3 DAT drive (12Gb+compression),
  I begin to wonder at the usefulness of stackers. Since backup speeds
  (esp of old disks on old clients over a net) can be much slower that the
  theoretical speed of the drive, we find oursleves here in the position
  of not needing a stacker, since at 350Kbyte/s average, it takes us 12
  hours to fill a tape to 16Gb (this is the typical compression we get).
  So apart from multiple backups over the weekend, or lazyness (only change
  the tapes once every few days), starkers dont offer us any advantage.
  Of course your mileage (and your tape writing speed) may vary....

From: Jim Harmon <>

  We're using an HP CS1553-A 4mm tape changer.
  It looks like a single tape device as far as SunOS is concerned (no
  special commands to change the tapes externally) but our restores are
  not automated, so this hasn't been a problem.
  I've heard there is a "robot-control" card that can be purchased for
  full control of the tape changer, but I don't have any details on where
  to get it. (I couldn't find one on HP's Web site.)
  The tape cartridge holds either 5 tapes and a cleaning cassette, or 6
  We use a basic shell script to execute the "mt" command option "offline"
  and that unloads the current tape and loads the next sequential one. We
  use one tape per server, and don't come close to filling the tapes, so 5
  tapes is all we need right now. I manually change the cartridge daily.

From: Tim Thompson <>

  I saw a 32 GB (total) 4 tape swapper/stacker at: they release about 5/week and then they
  "magically" get more.... they end up around $500 with the tapes included.
  don't know about compatability, just thought it was worth mentioning.

From: "Dan A. Zambon" <>

  Hey Craig,
  By stacker I assume you mean the generic tape stackers that I see advertised
  by a few vendors. If so, I have some info for you. By the way, these
  are 8mm stackers, not 4mm, so take this for what it's worth....

  We currently have two tape stacker units by MTI. One is a 7 tape, gravity
  fed 75GB capacity system with hardware compression. The second is a robotic
  arm (horizontal type), 10 tape 100GB tape stacker with hardware compression.

  My overall impression of them? They are horrible, unreliable time-consuming
  pieces of ....well, you know....
  Reason: They are unreliable. We have had problem after problem with them,
  from not accepting tapes, to not loading tapes to just flat stopping without
  a reason.
  Some notes:
  -we found that we MUST use D8 certified exabyte tapes, especially in the 10
   tape stacker. With the higher compression rate, we just got constant write
  -we have had a lot of trouble with the actual exabyte drives, especially in
   the 10 tape stacker because it is mounted vertically. If the tape drive
   isn't smooth in it's release of the tape, the pickup arm drops it.
  - with the 7 tape stacker, we have had troubles with all phases of the
   process. Sometimes the mechanism will not extract the current tape from
   the drive correctly. Sometimes the next tape will not slide into
   the tape drive correctly. And I have even see tapes misejected so
   that they are laying on top of the actual tape drive!
  I hope this information helps. I now know that the reason that I am
  almost completely bald at 48 is a) because of 13 year old daughters,
  and b) these &^&$#$% tape stackers!
From: Tom Powers <>

  Hewlett Packard makes an excellent light to moderate duty unit for which
  I can pass on two cavats.
  1) Budget for replacement tape carriages (the unit that holds the tape)
  in about 6 to 9 months, they wear out.
  2) Buy it from HP, or at a minimum make sure it's still HP branded and
  not an HP unit that has been relabeled. When we ran into some problems
  with a unit getting out of alignment (Worn Carriage was the problem) we
  went crazy trying to get someone to talk to since the reseller (Artecon)
  no longer handled them and HP washed their hands of the unit as soon as
  it got the Artecon sticker.
  Overall though the units performed well for 2 or 3 years of two tape a
  night backups,

From: "Charlie Mengler" <>

  I've got three of the four SUN cartridge 4mm drives. About once a month one of
  them refuses to open up & ejects its contents. This is REAL annoying! I'd
  strongly suggest going with DLT over 4mm. They could NOT be worse than what
  I experiencing.


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