[linux-lvm] dev node change

[Umar Draz]

Hi All

I have a SCSI share which i am using linux initiator on my ubuntu. Its
available for me in /dev/sdb

No I have created lvm group using the /dev/sdb. Today I just logut and
login my scsi share but this time ubutnu gave me this as /dev/sdc instead
of /dev/sdb.

due to this my lvm group is stuck, and its giving me the error

Input/output error

on pvdisplay or vgdisplay,

Any body help me how I can reslove this issue.?

Br.

Umar

[Peter Rajnoha]

Post by Umar Draz
Hi All
I have a SCSI share which i am using linux initiator on my ubuntu. Its
available for me in /dev/sdb
No I have created lvm group using the /dev/sdb. Today I just logut and
login my scsi share but this time ubutnu gave me this as /dev/sdc
instead of /dev/sdb.
due to this my lvm group is stuck, and its giving me the error
Input/output error
on pvdisplay or vgdisplay,
Any body help me how I can reslove this issue.?

You should always deactivate your LVM volumes before
disconnecting the underlying iSCSI volumes and then when
you reconnect the iSCSI back, activate the LVM volumes
(or if autoactivation is used - meaning use_lvmetad=1
is set in lvm.conf, this activation happens automatically).

Alternatively, you can call vgchange --refresh when the
iSCSI is connected back.

[Alessandro MACUZ]

Post by Peter Rajnoha

Post by Umar Draz
Hi All
I have a SCSI share which i am using linux initiator on my ubuntu. Its
available for me in /dev/sdb
No I have created lvm group using the /dev/sdb. Today I just logut and
login my scsi share but this time ubutnu gave me this as /dev/sdc
instead of /dev/sdb.
due to this my lvm group is stuck, and its giving me the error
Input/output error
on pvdisplay or vgdisplay,
Any body help me how I can reslove this issue.?

You should always deactivate your LVM volumes before
disconnecting the underlying iSCSI volumes and then when
you reconnect the iSCSI back, activate the LVM volumes
(or if autoactivation is used - meaning use_lvmetad=1
is set in lvm.conf, this activation happens automatically).
Alternatively, you can call vgchange --refresh when the
iSCSI is connected back.

Couldn't be used the identification of PV by UUID here? It should be better
imo.

Alex

[Peter Rajnoha]

Post by Umar Draz

Post by Umar Draz
Hi All
I have a SCSI share which i am using linux initiator on my

ubuntu. Its

Post by Umar Draz
available for me in /dev/sdb
No I have created lvm group using the /dev/sdb. Today I just logut and
login my scsi share but this time ubutnu gave me this as /dev/sdc
instead of /dev/sdb.
due to this my lvm group is stuck, and its giving me the error
Input/output error
on pvdisplay or vgdisplay,
Any body help me how I can reslove this issue.?

You should always deactivate your LVM volumes before
disconnecting the underlying iSCSI volumes and then when
you reconnect the iSCSI back, activate the LVM volumes
(or if autoactivation is used - meaning use_lvmetad=1
is set in lvm.conf, this activation happens automatically).
Alternatively, you can call vgchange --refresh when the
iSCSI is connected back.
Couldn't be used the identification of PV by UUID here? It should be
better imo.

Well, this is about dm tables that represent the logical volumes
(you can check dmsetup table output). The PV UUID doesn't play a role
at this level - the PV UUID is just LVM abstraction that is using
device-mapper kernel capabilities.

And if the iSCSI is disconnected while there's anything on top of it
(in this case the LV), the major:minor pair (as well as the kernel name)
is reserved until all the stack above it is freed.

Then when the iSCSI is connected back (while the old major:minor is
still held by old mapping), kernel has no other choice just to assign
new major:minor pair. Therefore we need a refresh (or deactivation/activation)
which will generate a new mapping with the new major:minor pair of the
underlying PV (the iSCSI volume).

[Umar Draz]

Hi Alex,

Thanks for this. :)

Br.

Umar


On Tue, Dec 10, 2013 at 7:33 PM, Alessandro MACUZ <

Post by Alessandro MACUZ

Post by Peter Rajnoha

Post by Umar Draz
Hi All
I have a SCSI share which i am using linux initiator on my ubuntu. Its
available for me in /dev/sdb
No I have created lvm group using the /dev/sdb. Today I just logut and
login my scsi share but this time ubutnu gave me this as /dev/sdc
instead of /dev/sdb.
due to this my lvm group is stuck, and its giving me the error
Input/output error
on pvdisplay or vgdisplay,
Any body help me how I can reslove this issue.?

You should always deactivate your LVM volumes before
disconnecting the underlying iSCSI volumes and then when
you reconnect the iSCSI back, activate the LVM volumes
(or if autoactivation is used - meaning use_lvmetad=1
is set in lvm.conf, this activation happens automatically).
Alternatively, you can call vgchange --refresh when the
iSCSI is connected back.

Couldn't be used the identification of PV by UUID here? It should be
better imo.
Alex
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