[linux-lvm] LVM over iSCSI

[linux-lvm] LVM over iSCSI

[Roberto Sassu]

Hi all

i configured a LVM volume group using two iSCSI devices as
physical volumes.
I designed one node (A) to create snapshots of a Logical Volume,
called 'lv_origin' and i want other nodes (B, C) access them
exclusively.
I assume that 'lv_origin' is never modified after the first snapshot
is created.
So, A first creates 'lv_origin' and then a snapshot called
'lv_snap1', which is available for this node.
The node B executes the command 'vgscan' and 'vgchange -ay'.
In this way, 'lv_origin' and 'lv_snap1' become available for B.
Next step, A creates a new snapshot of 'lv_origin' called
'lv_snap2'. This is not available for B and the only way that i
found to use it is to perform (on the node B) the following
commands:

1) vgscan
2) vgchange -an
3) vgchange -ay

However this procedure is not applicable if one of created
LVs is in use. How to solve this issue?

Thanks in advance for replies

Roberto Sassu

Re: [linux-lvm] LVM over iSCSI

[Ray Morris]

What says lvscan -vv ?
--
Ray Morris
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On 01/05/2011 11:48:54 AM, Roberto Sassu wrote:
> Hi all
> 
> i configured a LVM volume group using two iSCSI devices as
> physical volumes.
> I designed one node (A) to create snapshots of a Logical Volume,
> called 'lv_origin' and i want other nodes (B, C) access them
> exclusively.
> I assume that 'lv_origin' is never modified after the first snapshot
> is created.
> So, A first creates 'lv_origin' and then a snapshot called
> 'lv_snap1', which is available for this node.
> The node B executes the command 'vgscan' and 'vgchange -ay'.
> In this way, 'lv_origin' and 'lv_snap1' become available for B.
> Next step, A creates a new snapshot of 'lv_origin' called
> 'lv_snap2'. This is not available for B and the only way that i
> found to use it is to perform (on the node B) the following
> commands:
> 
> 1) vgscan
> 2) vgchange -an
> 3) vgchange -ay
> 
> However this procedure is not applicable if one of created
> LVs is in use. How to solve this issue?
> 
> Thanks in advance for replies
> 
> Roberto Sassu
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> 

Re: [linux-lvm] LVM over iSCSI

[Roberto Sassu]

Hi Ray

On Wednesday, January 05, 2011 09:53:33 pm Ray Morris wrote:
> What says lvscan -vv ?

lvscan tells the 'Original' LV is inactive, 'lv_snap1' is active,
'lv_snap2' is inactive.
Executing 'lvchange -ay lv_origin' does not change the status
of 'lv_snap2'.
If i run the command 'vgchange -ay' without 'vgchange -an',
i get this error message:

_get_device_info: device not found


Thanks

Roberto Sassu


> --
> Ray Morris
> support@bettercgi.com
> 
> Strongbox - The next generation in site security:
> http://www.bettercgi.com/strongbox/
> 
> Throttlebox - Intelligent Bandwidth Control
> http://www.bettercgi.com/throttlebox/
> 
> Strongbox / Throttlebox affiliate program:
> http://www.bettercgi.com/affiliates/user/register.php
> 
> On 01/05/2011 11:48:54 AM, Roberto Sassu wrote:
> > Hi all
> > 
> > i configured a LVM volume group using two iSCSI devices as
> > physical volumes.
> > I designed one node (A) to create snapshots of a Logical Volume,
> > called 'lv_origin' and i want other nodes (B, C) access them
> > exclusively.
> > I assume that 'lv_origin' is never modified after the first snapshot
> > is created.
> > So, A first creates 'lv_origin' and then a snapshot called
> > 'lv_snap1', which is available for this node.
> > The node B executes the command 'vgscan' and 'vgchange -ay'.
> > In this way, 'lv_origin' and 'lv_snap1' become available for B.
> > Next step, A creates a new snapshot of 'lv_origin' called
> > 'lv_snap2'. This is not available for B and the only way that i
> > found to use it is to perform (on the node B) the following
> > commands:
> > 
> > 1) vgscan
> > 2) vgchange -an
> > 3) vgchange -ay
> > 
> > However this procedure is not applicable if one of created
> > LVs is in use. How to solve this issue?
> > 
> > Thanks in advance for replies
> > 
> > Roberto Sassu
> > 
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] LVM over iSCSI

[Roberto Sassu]

Ok, i made some progresses.
First, i can propagate the device mapper configuration for
the created snapshot 'lv_snap2' on other nodes by executing:

1) lvscan
2) lvchange --refresh vg_local

Last command returns these messages:

---
_get_device_info: device not found
_get_device_info: device not found
vg_local/snapshot1: snapshot segment monitoring function failed.
---

However the device mapper configurations seems ok,
because the command 'dmsetup table' shows entries
related to 'lv_snap2'.
Then, i removed the snapshot from the node that created
it and i tried to propagate the change on another node by
executing same commands above.
The command lvchange reports this message:

---
Unable to deactivate open vg_local-lv_origin (253:5)
---

and the device mapper configuration is not changed.
How i can remove device mapper entries on other nodes?

Thanks

Roberto Sassu


On Thursday, January 06, 2011 11:34:50 am Roberto Sassu wrote:
> Hi Ray
> 
> On Wednesday, January 05, 2011 09:53:33 pm Ray Morris wrote:
> > What says lvscan -vv ?
> 
> lvscan tells the 'Original' LV is inactive, 'lv_snap1' is active,
> 'lv_snap2' is inactive.
> Executing 'lvchange -ay lv_origin' does not change the status
> of 'lv_snap2'.
> If i run the command 'vgchange -ay' without 'vgchange -an',
> i get this error message:
> 
> _get_device_info: device not found
> 
> 
> Thanks
> 
> Roberto Sassu
> 
> 
> > --
> > Ray Morris
> > support@bettercgi.com
> > 
> > Strongbox - The next generation in site security:
> > http://www.bettercgi.com/strongbox/
> > 
> > Throttlebox - Intelligent Bandwidth Control
> > http://www.bettercgi.com/throttlebox/
> > 
> > Strongbox / Throttlebox affiliate program:
> > http://www.bettercgi.com/affiliates/user/register.php
> > 
> > On 01/05/2011 11:48:54 AM, Roberto Sassu wrote:
> > > Hi all
> > > 
> > > i configured a LVM volume group using two iSCSI devices as
> > > physical volumes.
> > > I designed one node (A) to create snapshots of a Logical Volume,
> > > called 'lv_origin' and i want other nodes (B, C) access them
> > > exclusively.
> > > I assume that 'lv_origin' is never modified after the first snapshot
> > > is created.
> > > So, A first creates 'lv_origin' and then a snapshot called
> > > 'lv_snap1', which is available for this node.
> > > The node B executes the command 'vgscan' and 'vgchange -ay'.
> > > In this way, 'lv_origin' and 'lv_snap1' become available for B.
> > > Next step, A creates a new snapshot of 'lv_origin' called
> > > 'lv_snap2'. This is not available for B and the only way that i
> > > found to use it is to perform (on the node B) the following
> > > commands:
> > > 
> > > 1) vgscan
> > > 2) vgchange -an
> > > 3) vgchange -ay
> > > 
> > > However this procedure is not applicable if one of created
> > > LVs is in use. How to solve this issue?
> > > 
> > > Thanks in advance for replies
> > > 
> > > Roberto Sassu
> > > 
> > > _______________________________________________
> > > linux-lvm mailing list
> > > linux-lvm@redhat.com
> > > https://www.redhat.com/mailman/listinfo/linux-lvm
> > > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> > 
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 

[linux-lvm] lvm over iscsi

[jmfaidy]

Hi,
I asked this question in icsci mailing list, with no answer, so I try here.
I'm using fc6 2.6.20 as target and 2.18fc6-xen as initiator, my goal  
is to export a volume group from the target, in order to be abale to  
make a lvscan on the initiator, but i don't succeed.

  iscsiadm --mode node --targetname iqn.2007-05.fr.aic:jimiscsi  
--portal 10.0.22.133:3260 --login

-> end with no error, but i have nothing in /proc/scsi/scsi and no  
volume are detected by lvscan.

is it possible to export volume group instead of logical ?

Thx for any answer or clue...

JiM

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Re: [linux-lvm] lvm over iscsi

[Gordon McLellan]

Hello,

I'm guessing, from my own experiences with lvm, you'll have to either
export the bottom (the PV), or the top (the LV).   Trying to export
the middle puts it out of context.  A logical volume can't be detected
unless its physical volume is detected first (by the kernel?).

I wonder what pvcreate thinks of iscsi volumes.  could you create a pv
on an iscsi volume which is just an exported lv off another server?

Gordon


On 4/24/07, jmfaidy@aic.fr <jmfaidy@aic.fr> wrote:
> Hi,
> I asked this question in icsci mailing list, with no answer, so I try here.
> I'm using fc6 2.6.20 as target and 2.18fc6-xen as initiator, my goal
> is to export a volume group from the target, in order to be abale to
> make a lvscan on the initiator, but i don't succeed.
>
>   iscsiadm --mode node --targetname iqn.2007-05.fr.aic:jimiscsi
> --portal 10.0.22.133:3260 --login
>
> -> end with no error, but i have nothing in /proc/scsi/scsi and no
> volume are detected by lvscan.
>
> is it possible to export volume group instead of logical ?
>
> Thx for any answer or clue...
>
> JiM
>
> ----------------------------------------------------------------
> This message was sent using IMP, the Internet Messaging Program.
>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

Re: [linux-lvm] lvm over iscsi

[jmfaidy]

Thx for answering and giving me this information.
I've just tryed what you asked me to try.

So i succesfully created a pv, vg, lv on an exported lv from my iscsi target.

So, i'll find an other way, i hope.
tx

JiM


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