ITEM: G5146L
Problems with creating a mksysb at 3.2.0.
Question:
I am running into problems trying to run an automated tape backup.
The level of AIX is 3.2.0. IBM has been out to change the drive
but that has not done anything. I get the following errors:
0511-171 tar: reached end of media
and
0512-005 mksysb: problems in making system backup
Response:
You say that the problem started after you extended a filesystem.
Since then, you are not able to backup your system. Neither the
'mksysb', nor the 'backup' are working. It appears that you have
a script file that invokes the mksysb script file at 5:00 AM in
the morning.
We checked the block size and the density setting and they were
set to "512" and "0". I told you to leave the block size
as it is and to change the density setting to "17" (17 is for
525 MB 1/4" tapes).
It appears that your script file is NOT handling the second
tape error message. This is a known defect for 3.2.0.
You now have several choices to fix this:
1) Attach a larger tape drive with matching larger tapes and try
again.
2) Decrease the size of rootvg, and try again. You can do this by
unmounting one or more of your filesystems in rootvg, and trying
again. Note that if you do this, they will not be recreated
or the data restored upon installation of your machine from
this tape.
3) Installing the PTF fix for the end-of-tape error message. The
APAR number for this is IX27614, and you can call Defect Support.
There is also a work around for this end-of-tape error message.
This is as follows:
WORKAROUND FOR MKSYSB END-OF-TAPE DETECTION PROBLEM
PROCEDURE
This workaround will allow the mksysb command to correctly
bridge to a second or third tape.
NOTE: This modification is ONLY for a SINGLE tape/tape-
drive combination. Determine what tape and tape drive you
will be using for the backup before performing this
workaround.
NOTE: When running mksysb after this procedure, be sure to
use the correct density setting to match the rmtX special
device. For more information on density settings, order
document \#1896 from the IBM Fax Information Service
(1-800-IBM-4FAX).
1. Make a backup copy of /usr/bin/mksysb.
2. Use the following table to determine which "-S SIZEb"
flag needs to be added to the tar command at the end of
/usr/bin/mksysb. "SIZE" is the size in 512-byte blocks
to be expected from the tape.
NOTE: After the number for the -S flag, you must put in
| the "b" flag to denote these are blocks, e.g., "-S
| 111100b".
NOTE: The block-size setting for a 1/4-inch tape drive
should be 512 and for an 8mm or 4mm dat tape drive
should be 1024. However, if you are using a 7208 8mm
tape drive and you do not have PTF U403173 on your
system, you must use a block size of 512 and a SIZE flag
| of "-S 111100b" (half the value shown in the table).
The capacity in this case will be 1.15GB.
+----------------------------------+----------------+----------------+
| TAPE DRIVE | FLAG | CAPACITY |
+----------------------------------+----------------+----------------+
| 7206 4mm dat | -S 222200 | 2.3 Gbytes |
+----------------------------------+----------------+----------------+
| 7208 8mm | -S 222200 | 2.3 Gbytes |
+----------------------------------+----------------+----------------+
| 7207-001 1/4 inch | | |
+----------------------------------+----------------+----------------+
| 6150 tape | -S 14000 | 150 Mbytes |
+----------------------------------+----------------+----------------+
| 6250 tape | -S 23800 | 250 Mbytes |
+----------------------------------+----------------+----------------+
| 7207-011 1/4 inch | | |
+----------------------------------+----------------+----------------+
| 6150 tape | -S 14000 | 150 Mbytes |
+----------------------------------+----------------+----------------+
| 6250 tape | -S 23800 | 250 Mbytes |
+----------------------------------+----------------+----------------+
| 6525 tape | -S 50800 | 525 Mbytes |
+----------------------------------+----------------+----------------+
| 7207-012 1/4 inch | | |
+----------------------------------+----------------+----------------+
| 6150 tape | -S 14000 | 150 Mbytes |
+----------------------------------+----------------+----------------+
| 6250 tape | -S 23800 | 250 Mbytes |
+----------------------------------+----------------+----------------+
| 6525 tape | -S 104700 | 1.2 Gbytes |
+----------------------------------+----------------+----------------+
| NOTE: Because the meaning of the tar flag "-S" has changed at |
| some point in the past, it is necessary to perform a test to |
| determine if any adjustment in the number shown in the above chart |
| is needed. |
| |
| The following test can be used to determine any adjustment to the |
| supplied values of S in this document. Use \ to terminate |
| the test after tar asks for another volume. |
| |
| tar -cvf /dev/null -S100b / |
| |
| You will see something that looks like this: |
| |
| tar: There are 100 blocks on /dev/null. |
| tar: Mount next media on device /dev/null and press return. |
| |
| If it asks for the second volume after 2000 blocks, use the |
| numbers supplied in the fax. |
| |
| If it asks for the second volume after 100 blocks, multiply the |
| number in the fax by 20 and use that value. |
+--------------------------------------------------------------------+
3. Add the proper "-S SIZEb" flag to the /usr/bin/mksysb
file.
The original line looks like this:
tar -cvdpf"$DEVICE" -L"$archive_lst"
The corrected line should look like this (where SIZE is
chosen from the table in step 2):
tar -cvdpf"$DEVICE" -S SIZEb -L"$archive_lst"
EXAMPLE: For a 7208 8mm tape drive:
tar -cvdpf"$DEVICE" -S 222200b -L"$archive_lst"
You have decided to purchase a new tape drive model 7207-012, and you
still receive errors when trying to make a mksysb backup.
When you try this again, you get the following errors:
0301-164 bosboot : boot image is 3097 512 byte blocks.
0301-161 bosboot : dd failed to copy /dev/rmt0.1
0301-165 bosboot : WARNING! bosboot failed - do not attempt to
boot device.
0512-0016 mksysb : attempt to create a bootable tape failed :
bosboot -d /dev/rmt0.1 -a failed with return code 48.
I asked you to type df and check the size of your filesystems. It
appears that you did not have enough room in /tmp. You only had
about 7.6 MB and you need 8 MB. We increased the size of /tmp by
smit chfs, choosing Change / Show Characteristics of a Journaled
File System, choosing /tmp, and changing 16384 (512 byte blocks)
to 24576, which increases /tmp by 1 PP (4 MB). After we did this,
we tried the mksysb command again, and it failed again with another
error.
This time, the error indicated that the device was not present,
and we did a lsdev -Cc tape, and it showed that the tape was only
defined, and not available. We rebooted the machine, and the tape
drive came up available. We then typed "smit tape", chose Change / Show
Characteristics of a Tape Drive, and chose /dev/rmt0. We changed
density setting \#1 to 21 (for 1.2 GB 1/4" tapes), and \#2 to 17. This
will allow the 1/4 inch tape drive to write in 1.2 GB 1/4" density
setting while using high density (rmt0-rmt0.3) and 525 MB density
when using the lower density (rmt0.4-rmt0.7). Next, we did a
mkszfile at the prompt, and this worked. Next, we typed:
mksysb /dev/rmt0.1
This time it was successful!
For more information about the tape drives, you can research about
them using Info Explorer.
Support Line: Problems with creating a mksysb at 3.2.0. ITEM: G5146L
Dated: April 1994 Category: N/A
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