CentOS - Feb 2019 - 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.


-- 
Viele Gr??e
Helmut Drodofsky

Internet XS Service GmbH
He?br?hlstra?e 15
70565 Stuttgart

Gesch?ftsf?hrung
Helmut Drodofsky
HRB 21091 Stuttgart
USt.ID: DE190582774
Fon: 0711 781941 0 <tel:+497117819410>
Fax: 0711 781941 79
Mail: info at internet-xs.de
www.internet-xs.de

On Thu, 2019-02-07 at 10:56 +0100, Helmut Drodofsky
wrote:
> 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.
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.
> 
> 
-- 
Ron Loftin			reloftin at twcny.rr.com

"God, root, what is difference ?"	Piter from UserFriendly

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 Gr??e
Helmut Drodofsky

Internet XS Service GmbH
He?br?hlstra?e 15
70565 Stuttgart

Gesch?ftsf?hrung
Helmut Drodofsky
HRB 21091 Stuttgart
USt.ID: DE190582774
Fon: 0711 781941 0 <tel:+497117819410>
Fax: 0711 781941 79
Mail: info at internet-xs.de
www.internet-xs.de
Am 07.02.2019 um 16:17 schrieb Ron Loftin:
> On Thu, 2019-02-07 at 10:56 +0100, Helmut Drodofsky wrote:
>> 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.
> 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.
>
>>