SUMMARY: 4mm Dat Autoloader

From: Michael Duncan (michael.duncan@tti.fingerhut.com)
Date: Wed Nov 30 1994 - 08:43:20 CST


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Back on Nov.18 I wrote:

> Recently I installed a 20 Gbyte 4mm Tape Autoloader which uses 4 standard
>4mm DDS data cartridges in a tape magazine. The current backup software
>package I am using is Networker for Solaris 4.0.2. on SunOS 5.3.
>
> The problem that I am having is with the tape capacity. I am
>using 90 meter tapes. According to the documentation of the Autoloader
>I should be getting aprox 5 Gbytes.
>
>Here are the results so far. Actual Data
> Using Networker 3.368 Gbytes
> Using Ufsdump 3.457 Gbytes
>
>I have used /dev/rmt/0hbn
> 0cbn
> 0cn
> 0n
> 0un
>
>
>Total bytes were dirived from Networker information and the Ufsdump tty
>output and compared with physical disk.

Well this has been an interesting problem. Most of the results I believe
are specific to the Sun 4mm Archive 20 Gbyte Autoloader.

Not long after posting my problem I recieved bugid 118096 from SUN stating the
4mm Archive Autoloader has not shown that it can backup anywhere near its
publicized capacity. Their results correspond with mine. SUN support
told me there was no fix for this problem.

According to SUN the 90m tapes will hold about 2.0 Gbytes of information
in an uncompressed form. The reason I was able to get 3.3 Gbytes was that
compression was being done by the hardware.

I would like to thank the following for their input.
Sorry it took me so long to SUMMARIZE..........

Phil.Schackman@seag.fingerhut.com
rwh@atmos.albany.edu
Richard.Skelton@brake.demon.co.uk
blymn@awadi.com.AU
martin@gea.hsr.it
epl@Kodak.COM
chaos!jordan.wfg.com!mam@uunet.uu.net
paulo@dcc.unicamp.br

Michael Duncan
Tennessee Telemarketing, Inc.
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 Bug Id: 1181096
 Category: hardware
 Subcategory: tape
 Release summary: s1093
 Synopsis: 4mm Autoloader is not capable of storing near suggested capacity
         Integrated in releases:
 Patch id:
 Description:
4mm Archive Autoloader has not shown that it can backup anywhere near its
publicsized capacity. Typically the maximum that it has been capable of store
has been closer to 2.9GB not 5.0GB. I have tried may different combinations of
options to ufsdump while attempting to backup a 3.1GB filesystem. This file-
system is mostly text data which will compress with unix "compress" to 1.966GB .
Filesystem is /slap/support. Using dd with a 12MB textfile I was able to store a
max of 3.6GB to the device, this file compressed to 6.29MB. Though it is obvious
that the device is capable of storing a reasonable amount of data,considering the
type of files being used, in the customer's viewpoint is the device is falling far short
 of its expected capacity.

testcase: Files are on system flap, /corefiles/mcroke

tape.sh:
#! /bin/sh
#

echodo()
    {
    echo "+ $*"
    $*
    return $?
    }

DEV=/dev/rmt/2bn
LOOPCOUNT=1
LOGFILE="test.log"
TESTFILE="testfile-cpio"
(
echo "----Starting Test --"
echodo mt -f $DEVrewind
while echodo dd if=$TESTFILE of=$DEV bs=112k ; do
        echo "$LOOPCOUNT done."
        LOOPCOUNT=` expr $LOOPCOUNT + 1`
done
) > $LOGFILE 2>&1

  tail of log files:
 test.log_cpio.bn.112k
109+1 records out
305 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2bn bs=112k
109+1 records in
109+1 records out
306 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2bn bs=112k
dd: unexpected short write - wrote only 65534 bytes, expected 114688
1+0 records in
1+0 records out
                ----------------------------------------
test.log_cpio.cn.112k
109+1 records out
305 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2cn bs=112k
109+1 records in
109+1 records out
306 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2cn bs=112k
dd: unexpected short write - wrote only 65534 bytes, expected 114688
1+0 records in
1+0 records out
                ----------------------------------------
 test.log_cpio.bn.56k
218+1 records out
305 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2bn bs=56k
218+1 records in
218+1 records out
306 done.
+ dd if=/corefiles/mcroke/testfile-cpio of=/dev/rmt/2bn bs=56k
dd: unexpected short write - wrote only 0 bytes, expected 57344
2+0 records in
2+0 records out
                ----------------------------------------
ufsdump info
# /usr/ucb/du -s /support
3127676 /support
# df -k /support
Filesystem kbytes used avail capacity Mounted on
/dev/md/dsk/d15 9758338 3127676 5654832 36% /support
# ufsdump 0ucbf 56 flap-lab:/dev/rmt/2c /support
  DUMP: Date of this level 0 dump: Wed Oct 26 07:44:30 1994
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/md/rdsk/d15 (/support) to /dev/rmt/2c on host flap-lab
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 6353996 blocks (3102.54MB)
  DUMP: Writing 28 Kilobyte records
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 2.68% done, finished in 3:01
  DUMP: 6.27% done, finished in 2:29
  DUMP: 10.47% done, finished in 2:08
  DUMP: 15.62% done, finished in 1:48
  DUMP: 20.50% done, finished in 1:36
  DUMP: 24.46% done, finished in 1:32
  DUMP: 28.14% done, finished in 1:29
  DUMP: 32.58% done, finished in 1:22
  DUMP: 37.19% done, finished in 1:15
  DUMP: 41.72% done, finished in 1:09
  DUMP: 46.29% done, finished in 1:03
  DUMP: 50.99% done, finished in 0:57
  DUMP: 55.95% done, finished in 0:51
  DUMP: 60.77% done, finished in 0:45
  DUMP: 65.27% done, finished in 0:39
  DUMP: 69.61% done, finished in 0:34
  DUMP: 73.94% done, finished in 0:29
  DUMP: 78.60% done, finished in 0:24
  DUMP: 83.41% done, finished in 0:18
  DUMP: 88.09% done, finished in 0:13
  DUMP: 93.12% done, finished in 0:07
  DUMP: End-of-tape detected
  DUMP: Tape rewinding
  DUMP: 94.95% done, finished in 0:05
  DUMP: Change Volumes: Mount volume #2
  DUMP: NEEDS ATTENTION: Is the new volume (#2) mounted and ready to go?: ("yes" or "no")
  DUMP: The ENTIRE dump is aborted.
 Summary:
4mm Autoloader is not capable of reaching its execpted capacity using ufsdump
 History:
         Submitter: michael.croke@east Date: 10/28/94
         Dispatch Operator: bugtraq Date: 10/28/94



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