Mounting a read only disk
Hello guys,
I'm having a problem I don't know how to solve.
I have a running system with its disk under LVM2. Physical disks
are in a SAN and we have no problems with them. Now we have configured an automated snapshots of our disks from our SAN to another one (both are HP 3par) and we want now the snapshot to be mounted in another system. This system has connected the snapshot disk without any problem but we can't mount the FS, because we can't activate volumes in it. The "only" difference between original disks and snaptshot ones are that this are seen by the OS as read only disks, so they can't be written.
In the system trying to mount the snapshot I could see PVs, VGs and
LVs, as:
amateo_adm@myotis52fa:~$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda5 Disk1 lvm2 a- 6.76g 0 /dev/sdb IndexesDisk lvm2 a- 69.98g 20.00g /dev/sdc UsersDisk lvm2 a- 2.50t 0 /dev/sdd UsersDisk lvm2 a- 1023.98g 499.97g amateo_adm@myotis52fa:~$ sudo vgs VG #PV #LV #SN Attr VSize VFree Disk1 1 2 0 wz--n- 6.76g 0 IndexesDisk 1 1 0 wz--n- 69.98g 20.00g UsersDisk 2 1 0 wz--n- 3.50t 499.97g amateo_adm@myotis52fa:~$ sudo lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert root Disk1 -wi-ao 5.82g swap_1 Disk1 -wi-ao 956.00m vol_indexes IndexesDisk -wi-d- 49.98g vol_users UsersDisk -wi-d- 3.01t
but I can't activate LVs:
amateo_adm@myotis52fa:~$ sudo lvchange -a y UsersDisk/vol_users device-mapper: reload ioctl failed: Invalid argument
and in the logs I get:
Jan 28 13:32:41 myotis52fa kernel: [ 1789.845945] device-mapper: table: 252:0: linear: dm-linear: Device lookup failed Jan 28 13:32:41 myotis52fa kernel: [ 1789.846047] device-mapper: ioctl: error adding target to table
the original system and the one trying to mount the snapshot are
both ubuntu 12.04 with same kernel (3.4.0-030400-generic) and version of lvm2 (2.02.66-4ubuntu7.4, the packaged by ubuntu).
Any help?
Signature · 7 lines
Angel L. Mateo Mart�nez Secci�n de Telem�tica �rea de Tecnolog�as de la Informaci�n y las Comunicaciones Aplicadas (ATICA) http://www.um.es/atica Tfo: 868887590 Fax: 868888337
hola Angel,
you need to present your snapshot as a RW LUN ; otherwise you won't be able to activate the VG.
As you should be writing your metadata to the snapshot the original data will remain unharmed.
Cheers
Fran
Quoted 68 lines · Angel L. Mateo
Hello guys,
I'm having a problem I don't know how to solve.
I have a running system with its disk under LVM2. Physical disks are
in a SAN and we have no problems with them. Now we have configured an automated snapshots of our disks from our SAN to another one (both are HP 3par) and we want now the snapshot to be mounted in another system. This system has connected the snapshot disk without any problem but we can't mount the FS, because we can't activate volumes in it. The "only" difference between original disks and snaptshot ones are that this are seen by the OS as read only disks, so they can't be written.In the system trying to mount the snapshot I could see PVs, VGs and
LVs, as:amateo_adm@myotis52fa:~$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda5 Disk1 lvm2 a- 6.76g 0 /dev/sdb IndexesDisk lvm2 a- 69.98g 20.00g /dev/sdc UsersDisk lvm2 a- 2.50t 0 /dev/sdd UsersDisk lvm2 a- 1023.98g 499.97g amateo_adm@myotis52fa:~$ sudo vgs VG #PV #LV #SN Attr VSize VFree Disk1 1 2 0 wz--n- 6.76g 0 IndexesDisk 1 1 0 wz--n- 69.98g 20.00g UsersDisk 2 1 0 wz--n- 3.50t 499.97g amateo_adm@myotis52fa:~$ sudo lvs LV VG Attr LSize Origin Snap% Move Log Copy% Convert root Disk1 -wi-ao 5.82g swap_1 Disk1 -wi-ao 956.00m vol_indexes IndexesDisk -wi-d- 49.98g vol_users UsersDisk -wi-d- 3.01tbut I can't activate LVs:
amateo_adm@myotis52fa:~$ sudo lvchange -a y UsersDisk/vol_users device-mapper: reload ioctl failed: Invalid argumentand in the logs I get:
Jan 28 13:32:41 myotis52fa kernel: [ 1789.845945] device-mapper: table: 252:0: linear: dm-linear: Device lookup failed Jan 28 13:32:41 myotis52fa kernel: [ 1789.846047] device-mapper: ioctl:error adding target to table
the original system and the one trying to mount the snapshot are both
ubuntu 12.04 with same kernel (3.4.0-030400-generic) and version of lvm2 (2.02.66-4ubuntu7.4, the packaged by ubuntu).Any help?
--
Angel L. Mateo Martínez
Sección de Telemática
Área de Tecnologías de la Información
y las Comunicaciones Aplicadas (ATICA)
http://www.um.es/atica
Tfo: 868887590
Fax: 868888337_______________________________________________
linux-lvm mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
El 28/01/14 16:22, Fran Garcia escribi�:
Quoted 8 lines
hola Angel,
you need to present your snapshot as a RW LUN ; otherwise you won't be able to activate the VG.
As you should be writing your metadata to the snapshot the original data will remain unharmed.
Ok. I'm going to try it. Thank you.
Signature · 7 lines
Angel L. Mateo Mart�nez Secci�n de Telem�tica �rea de Tecnolog�as de la Informaci�n y las Comunicaciones Aplicadas (ATICA) http://www.um.es/atica Tfo: 868887590 Fax: 868888337
El 29/01/14 08:58, Angel L. Mateo escribi�:
Quoted 12 lines
El 28/01/14 16:22, Fran Garcia escribi�:
Quoted 8 lines
hola Angel,
you need to present your snapshot as a RW LUN ; otherwise you won't be able to activate the VG.
As you should be writing your metadata to the snapshot the original data will remain unharmed.
Ok. I'm going to try it. Thank you.
It works now with RW LUNs. Thank you very much.
Signature · 7 lines
Angel L. Mateo Mart�nez Secci�n de Telem�tica �rea de Tecnolog�as de la Informaci�n y las Comunicaciones Aplicadas (ATICA) http://www.um.es/atica Tfo: 868887590 Fax: 868888337
Glad it's working for you now Angel. I noticed you had exactly the same error messages as I did in my post yesterday.
Was there any way of telling from the information you gave, or the output of any other command, if the LUNs are RW or RO?
Kind regards,
Sebastian
Quoted 41 lines
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Angel L. Mateo amateo-at-um.es |linux-lvm/Allow + Forward to Syn&Yahoo&Gmail|
Sent: 29 January 2014 11:45
To: ****************; ********************; *****************; [email protected]
Subject: Re: [linux-lvm] Mounting a read only diskEl 29/01/14 08:58, Angel L. Mateo escribi�:
Quoted 4 lines
El 28/01/14 16:22, Fran Garcia escribi�:
Quoted 3 lines
hola Angel,
you need to present your snapshot as a RW LUN ; otherwise
you won't be
Quoted 3 lines
Quoted 3 lines
able to activate the VG.
As you should be writing your metadata to the snapshot the
original data
Quoted 5 lines
Quoted 2 lines
will remain unharmed.
Ok. I'm going to try it. Thank you.
It works now with RW LUNs. Thank you very much.
Signature · 13 lines
Angel L. Mateo Mart�nez Secci�n de Telem�tica �rea de Tecnolog�as de la Informaci�n y las Comunicaciones Aplicadas (ATICA) http://www.um.es/atica Tfo: 868887590 Fax: 868888337 _______________________________________________ linux-lvm mailing list [email protected] https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
El 29/01/14 12:58, Seb A escribi�:
Quoted 6 lines
Glad it's working for you now Angel. I noticed you had exactly the same error messages as I did in my post yesterday.
Was there any way of telling from the information you gave, or the output of any other command, if the LUNs are RW or RO?
In my system, there are messages like:
Jan 28 14:15:25 myotis52fa kernel: [ 1.724926] sd 3:0:2:0: [sdc] Write Protect is on
Signature · 7 lines
Angel L. Mateo Mart�nez Secci�n de Telem�tica �rea de Tecnolog�as de la Informaci�n y las Comunicaciones Aplicadas (ATICA) http://www.um.es/atica Tfo: 868887590 Fax: 868888337