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/dev/rmt/0????

 
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Stephen Badgett
Regular Advisor

/dev/rmt/0????

What does each of these devices represent?

0m
0mb
0mn
0mnb
1m
1mb
1mn
1mnb
c0t3d0BEST ...

From what I have seen ...

/dev/rmt/0m -- rewind the tape to the start after any command

/dev/rmt/0mn -- no-rewind leave the tape at the position where the old command left off

Steve
Not as is, is now
8 REPLIES 8
Sundar_7
Honored Contributor
Solution

Re: /dev/rmt/0????

Hi Steve,

Run lssf command against the device files - will tell you the characteristics of each of the device files

# lssf /dev/rmt/0m
stape card instance 3 SCSI target 3 SCSI LUN 0 at&t best density available at address 0/4/0/0.3.0 /dev/rmt/0m
# lssf /dev/rmt/0mn
stape card instance 3 SCSI target 3 SCSI LUN 0 at&t no rewind best density available at address 0/4/0/0.3.0 /de
v/rmt/0mn
# lssf /dev/rmt/0mnb
stape card instance 3 SCSI target 3 SCSI LUN 0 berkeley no rewind best density available at address 0/4/0/0.3.0
/dev/rmt/0mnb
#

b = confirms to the berkeley standard - by default it is AT&T

c0t3d0BEST = uses best density available (software compression) - Same as 0m - no big difference.
Learn What to do ,How to do and more importantly When to do ?
Con O'Kelly
Honored Contributor

Re: /dev/rmt/0????

Hi Steve

You'll find a full explanation of the what each device file means in the man page:
# man mt

Cheers
Con
Con O'Kelly
Honored Contributor

Re: /dev/rmt/0????

sorry should have said:
# man 7 mt

Cheers
Con
edwin hamers
Advisor

Re: /dev/rmt/0????

Hi,

I was lately at a HP advanced Administrator Course, and there they adviced to use only the /dev/rmt/c0t3d0BEST device.

Chant and be happy
Stephen Badgett
Regular Advisor

Re: /dev/rmt/0????

Hello Edwin,

Thank you for your response.

I was using different device files with lots of success. The /dev/rmt/1nm type is great when I do not want the tape to rewind when a command has completed. Using this method I can continue a store later if needed and also store different versions of the same file on the same tape, that is a fine feature. The other device is useful when I just need to do one command and have it at BOT when done with that command, WOW I like that too.

Now with the device /dev/rmt/c0t3d0BEST is it going to know to rewind or not rewind when a store type command is giving, default being rewind? We have c0t0d0BESTnb and I guess that would be a NO-REWIND Berkley and c0t0d0BESTb would be REWIND Berkley, correct?

Steve
Not as is, is now
Sundar_7
Honored Contributor

Re: /dev/rmt/0????

Steve,

c0t0d0BESTnb = No-rewind Berkeley and uses the best compression possible

c0t0d0BESTb = Rewind Berkeley and again uses the best compression possible

-- Sundar.
Learn What to do ,How to do and more importantly When to do ?
RAC_1
Honored Contributor

Re: /dev/rmt/0????

If you do a ls -il on those files, you will see that the inode is same for most of them.
Like for 0m and for BEST.

So they are same, represeted in different way.

Anil
There is no substitute to HARDWORK
Stephen Badgett
Regular Advisor

Re: /dev/rmt/0????

YES

Thank you Anil that is just one more great answer and helps a great deal

Thank you

Steve
Not as is, is now