IBM RS/6000 - Manual (Page 109)

/home/george/tmp, then /home/george/tmp. will be backed up, but none of the
files contained within it will be backed up.
Make BOOTABLE backup?
This item applies to tapes only and will allow you to create a tape with or
without a boot image. Normally, you would leave this option to its default of
yes .
EXPAND /tmp if needed?
If you have answered yes to the previous option and are creating a bootable
tape, then there has to be enough space in /tmp to be able to create the boot
image before placing it on the tape. If there isn't enough space in /tmp to
create the image and this option is set to
yes , then the command will increase
/tmp for you (/tmp will not be reduced after the command has run).
You can determine how much space is required for the boot image by running
the command:
bosboot -q -a -d /dev/rmtx (where rmtx is the tape device, for
example rmt0). When you have determined how much space is required, you
can use the command
df -k to determine if you have enough space in the /tmp
filesystem. An example of this is shown below:
bosboot -q -a -d /dev/rmt
Filesystem
KB required
/tmp 8748
df -k
Filesystem
1 24-blocks Free %Used Iused %Iused Mounted on
/dev/hd4 4 96 1 4 98% 1 65 53% /
/dev/hd2 417792 614 99% 17119 17% /usr
/dev/hd9var 4 96 346 16% 132 13% /var
/dev/hd3 12288 114 4 8% 31 1% /tmp
/dev/hd1 4 96 392 5% 18 2% /home
In the example above, to create the boot image will require 8748 KB free in the
/tmp filesystem. The
df -k command shows that there is 11404 KB free in
/tmp, and in this case, /tmp would not have to be increased.
Number of BLOCKS to write in a single output
This allows you to alter how many 512-byte blocks are written in a single
operation to the tape device. Larger values will result in larger physical writes
to the tape.
5.4.3 Testing Your System Backup
When you have created a system backup, it is always good practice to test the
backup so that you can be sure that it will work in the event of an unforeseen
failure. When you create a backup, you can never be 100 percent sure that it has
been successful. The tape may be damaged or data wasn't written to tape due to
a defective tape, and this wasn't picked up by the backup process. Failures occur
infrequently, but when they, do it is best to be well prepared.
There is no complete way of testing your mksysb other than by performing a
complete restore, but you can go some way to making sure that the backup is valid
and will work.
You can verify the contents of your mksysb by using the SMIT fastpath:
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