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persistent generic device for tape changer

Hello,

mtx and therefor amanda use generic device /dev/sg<x> for tape changer.

These devices change on reboot.

How to make them persistent?

/dev/sch0 and /dev/sch1 seem to be persistent.

/dev/tape/by-id/ shows links from WWID to generic device

An UDEV rule could help? I have not found any example.

Comments

Re: persistent generic device for tape changer

By Ron Loftin at 02/07/2019 - 10:17

On Thu, 2019-02-07 at 10:56 +0100, Helmut Drodofsky wrote:
I had a similar issue when I moved to Mint 18 with the tape device.
 This works with kernel 4.10 and later.  Copy /lib/udev/rules.d/60-
persistent-storage-tape.rules to /etc/udev/rules.d and make a change as
shown:

diff -n /lib/udev/rules.d/60-persistent-storage-tape.rules
/etc/udev/rules.d/60-persistent-storage-tape.rules 
d9 1
a9 2
   SYMLINK+="changer"
#  SYMLINK+="tape/by-id/scsi-$env{ID_SERIAL}"

This created /dev/changer as a link to the /dev/sg<x> device that will
be consistent every time the system is booted.

Re: persistent generic device for tape changer

By Helmut Drodofsky at 02/07/2019 - 16:29

Hello Ron,

sounds good. I have 2 tape changer. I persume, udev creates the same
link for both.

Can I modify
SYMLINK+="changer-$env{ID_SERIAL}"

The serial should be unique.

Viele Grüße
Helmut Drodofsky

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Am 07.02.2019 um 16:17 schrieb Ron Loftin:

Re: persistent generic device for tape changer

By Ron Loftin at 02/07/2019 - 18:13

I've taken you as far as I can go.  Now you will have to experiment a
bit for your use case.  I should point out that at least in my system,
the link with the serial number in it shows up even with the line
commented in the rules file.

As always, YMMV.

On Thu, 2019-02-07 at 22:29 +0100, Helmut Drodofsky wrote:

Re: persistent generic device for tape changer

By Johnny Hughes v... at 02/08/2019 - 06:21

Maybe

.... ATTRS{serial}=="likethis16c07338d2a294c" , SYMLINK+="mybackup/changer1" ...

and for the second one

... ATTRS{serial}=="likethis9ae76c073f5ccb8" , SYMLINK+="mybackup/changer2" ...

?