CentOS - Feb 2019 - persistent generic device for tape changer

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.
>
>>

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:
> 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.
> > 
> > > 
> > > 
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
-- 
Ron Loftin			reloftin at twcny.rr.com

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

> Am 08.02.2019 um 00:13 schrieb Ron Loftin <reloftin at twcny.rr.com>:
> 
> On Thu, 2019-02-07 at 22:29 +0100, Helmut Drodofsky wrote:
>> 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
>> 
>> 
> 
> 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.
Maybe

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

and for the second one 

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

?

--
LF