/dev/rmt/0mn & /dev/rmt/1mn

[Rambo_1]

Hi,
when I used "make_tape_recovery -Av" to backup the OS,the os reported :"can't find the /dev/rmt/0mn".
the output after "ioscan -fnCtape " is:
tape 1 0/2/1/0.2.0 stape CLAIMED DEVICE HP C5683A
/dev/rmt/1m /dev/rmt/c4t2d0BESTn
/dev/rmt/1mb /dev/rmt/c4t2d0BESTnb
/dev/rmt/1mn /dev/rmt/c4t2d0DDS
/dev/rmt/1mnb /dev/rmt/c4t2d0DDSb
/dev/rmt/c4t2d0BEST /dev/rmt/c4t2d0DDSn
/dev/rmt/c4t2d0BESTb /dev/rmt/c4t2d0DDSnb

I found a "/dev/rmt/0mn" under /dev/rmt/ directory, I mean that there are two tape device file under /dev/rmt directory.one is /dev/rmt/0mn ,another is /dev/rmt/1mn.
How to change the "1mn" to default "0mn"

BR

[Bill Hassell]

Don't use the defaults. (I will resist saying that "Real sysadmins don't use defaults") ;-)

Device files point to devices. Your ioscan does not report /dev/rmt/0.. because there is no such device. Perhaps at one time there was a 0mn device but not anymore. The reason the device files are still there could be due to a variety of reasons. While there is a way to rmeove all the device files and kernel mappings, then recreate your existing tape with 0.. device file names, that is way too complicated. Just add the following option: -a /dev/rmt/1mn as in:

make_tape_recovery -AvI -a /dev/rmt/0mn

Note that I added the -I option so when you restore, you'll be able to select any changes before actually restoring the disk. If you just have a vg00, this is all you need. If you have other volume groups, add the -x inc_entire=vg00 option.

[venugopalakrishna.y.r]

hello rambo,
make_tape_recovery uses /dev/rmt/0mn as default destination. but yout tape drive has to be accessed using /dev/rmt/1mn.
therefore, use make_tape_recovery with -d option to specify /dev/rmt/1mn as the destination.
eg.
#make_tape_recovery -Av -d /dev/rmt/1mn

venu

[Petr Simik_1 · Accepted solution]

I use for my 1st DDS drive
make_tape_recovery -x inc_entire=vg00 -I -v -a /dev/rmt/0mn

or for 2nd my DLT drive

make_tape_recovery -a /dev/rmt/1mn -x inc_entire=vg00 -I -v

1st option : you have to learn to specify 1mn.
2nd option: you can make a symbolic link

# ln -s /dev/rmt/1m /dev/rmt/0m
# ln -s /dev/rmt/1mn /dev/rmt/0mn

By this you can simulate that you are having tape in 0mn.

[Bharat Katkar]

Hi,

1. make_tape_recovery -AvI -a /dev/rmt/0mn

2. Create link files. But in this case take care while adding any new tape device in future. It should not be 0m or else it clash with the existing one.

# ln -s /dev/rmt/0m /dev/rmt/1m
# ln -s /dev/rmt/0mn /dev/rmt/1mn

Regards,

[Rambo_1]

Hi ,Bill Hassell & Bharat Katkar
"make_tape_recovery -AvI -a /dev/rmt/0mn & make_tape_recovery -AvI -a /dev/rmt/1mn" didn't work . removed all the device files and kernel mappings, recreate the tape but the device file names still was /dev/rmt/1mn .
I "mv " the 1mn to 0mn , the make_tape_recovery -Av was OK !
I wonder if I should re-mv 0mn to 1mn and then use "# ln -s /dev/rmt/1m /dev/rmt/0m" to make it in effect ? what different between "mv" and "ln " ?

BR

[Bharat Katkar]

HI,
1. MV: Rename the files. Original Name gets lost.
2. LN: Creates Link to the file keeping the existing files untouched. File is accessible thr' two names. Even though they have two names they share same Inode.

Use LN instead of MV atleast for Special files.
Regards,

[Bill Hassell]

When you say "did not work", what was the error message?