[linux-lvm] vgchange -an question with disconnected disks

[linux-lvm] vgchange -an question with disconnected disks

[John DeFranco]

I have a question regarding the behavior of vgchange -a n on lvm2 when 
there are disk failures. Specifically the following:

1. vgchange -a y vg00
2. disconnect the disks
3. vgchange -a n vg00

Now this fails with many messages, such as:
[root@harris ~]# vgchange -a n vg00
   /dev/sda1: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdb1: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdb2: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdc1: read failed after 0 of 4096 at 0: Input/output error
   /dev/sda: read failed after 0 of 1024 at 0: Input/output error
   /dev/sda: read failed after 0 of 1024 at 312475648: Input/output error
   /dev/sda: read failed after 0 of 2048 at 0: Input/output error
   /dev/sda1: read failed after 0 of 4096 at 1966080: Input/output error
   /dev/sda1: read failed after 0 of 4096 at 0: Input/output error
   /dev/sda2: read failed after 0 of 4096 at 310312960: Input/output error
   /dev/sda2: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdb: read failed after 0 of 1024 at 0: Input/output error
   /dev/sdb: read failed after 0 of 1024 at 312475648: Input/output error
   /dev/sdb: read failed after 0 of 2048 at 0: Input/output error
   /dev/sdb1: read failed after 0 of 4096 at 1966080: Input/output error
   /dev/sdb1: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdb2: read failed after 0 of 4096 at 310312960: Input/output error
   /dev/sdb2: read failed after 0 of 4096 at 0: Input/output error
   /dev/sdc: read failed after 0 of 1024 at 0: Input/output error
   /dev/sdc: read failed after 0 of 1024 at 16384000: Input/output error
   /dev/sdc: read failed after 0 of 2048 at 0: Input/output error
   /dev/sdc1: read failed after 0 of 4096 at 16318464: Input/output error
   /dev/sdc1: read failed after 0 of 4096 at 0: Input/output error
   Unable to find volume group "vg00"
[root@harris ~]#

This the vg is not deactivated. Now this is different behavior that with 
lvm1 which would just proceed as normal. My question is that is there a 
way to force the deactivation to occur in this case?

Thanks!

-- 
===========
John DeFranco                  Hewlett Packard Company
john.defranco@hp.com           Availability Clusters Solution Lab
phone: 408 447-7543            19111 Pruneridge Ave., M/S 4101
fax:   408 447-0056            Cupertino, CA 95014

Re: [linux-lvm] vgchange -an question with disconnected disks

[Alasdair G Kergon]

On Thu, Feb 02, 2006 at 10:06:47AM -0800, John DeFranco wrote:
> My question is that is there a 
> way to force the deactivation to occur in this case?
 
Not from lvm2 unless you restore the metadata from a backup
first.

To remove the logical volumes from the kernel, use 'dmsetup'.
List what's there: dmsetup info -c
*After* ensuring the open count is 0, remove individually
with 'dmsetup remove' or all at once with 'dmsetup remove_all'.

Alasdair
-- 
agk@redhat.com

Re: [linux-lvm] vgchange -an question with disconnected disks

[Peter Smith]

John DeFranco wrote:

> I have a question regarding the behavior of vgchange -a n on lvm2 when 
> there are disk failures. Specifically the following:
>
> 1. vgchange -a y vg00
> 2. disconnect the disks
> 3. vgchange -a n vg00

Are you doing this in the correct order?  Shouldn't you _de_activate the 
VG _before_ removing the disks?  And besides, shouldn't you remove the 
offending disks from the VG _before_ deactivating and then removing the 
disks physically?  Or at least something equivalent.

1.  vgreduce vg00 <offending disks>
2.  vgchange -a n vg00
3.  disconnect the disks
4.  vgchange -a y vg00

...

Peter

Re: [linux-lvm] vgchange -an question with disconnected disks

[John DeFranco]

Actually I was not asking this question in the context removing a disk. 
I was asking if you loose connectivity to a disk(s) unexpectitly.

Peter Smith wrote:
> John DeFranco wrote:
> 
>> I have a question regarding the behavior of vgchange -a n on lvm2 when 
>> there are disk failures. Specifically the following:
>>
>> 1. vgchange -a y vg00
>> 2. disconnect the disks
>> 3. vgchange -a n vg00
> 
> Are you doing this in the correct order?  Shouldn't you _de_activate the 
> VG _before_ removing the disks?  And besides, shouldn't you remove the 
> offending disks from the VG _before_ deactivating and then removing the 
> disks physically?  Or at least something equivalent.
> 
> 1.  vgreduce vg00 <offending disks>
> 2.  vgchange -a n vg00
> 3.  disconnect the disks
> 4.  vgchange -a y vg00
> 
> ...
> 
> Peter
> 
> _______________________________________________
> 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/

-- 
===========
Cheers
-jd