[linux-lvm] clvm: failed to activate logical volumes sometimes

[emmanuel segura]

maybe you are using an old clvm version, I rember that in the new
version you don't need to execute any command on the secondary node.

2017-04-20 10:06 GMT+02:00 Eric Ren <zren at suse.com>:
> Hi!
>
> This issue can be replicated by the following steps:
> 1. setup two-node HA cluster with dlm and clvmd RAs configured;
> 2. prepare a shared disk through iscsi, named "sdb" for example;
>
> 3. execute lvm cmds on n1:
> lvm2dev1:~# pvcreate /dev/sdb
> Physical volume "/dev/sdb" successfully created
> lvm2dev1:~ # vgcreate vg1 /dev/sdb
>     Clustered volume group "vg1" successfully created
> lvm2dev1:~ # lvcreate -l100%VG -n lv1 vg1
>     Logical volume "lv1" created.
> lvm2dev1:~ # lvchange -an vg1/lv1
>
> 4. disconnect shared iscsi disk on n2;
> 5. to activate vg1/lv1 on n1:
> lvm2dev1:~ # lvchange -ay vg1/lv1
>     Error locking on node UNKNOWN 1084783200: Volume group for uuid not
> found: TG0VguoR1HxSO1OPA0nk737FJSQTLYAMKV2M20cfttItrRnJetTZmKxtKs3a88Ri
>
> 6. re-connect shared disk on n2;
> 7. execute `clvmd -R` on n1; and then I can activate lv1 successfully.
>
> In local mode, lvm will make a full scan on disks each time when lvmetad is
> disable. As we know,
> lvmetad is also disable when clvm is in use, so that  device cache can not
> be refreshed automatically
> when device is added or removed. We can solve this issue by executing "clvmd
> -R" manually. But,
> in some auto scripts, it's boring to put "clvmd -R" before some lvm commands
> everywhere.
>
> So, is there an option to enable full scan every time when lvm is invoked in
> cluster scenario?
> Thanks in advance:)
>
> Regards,
> Eric
>
> On 04/14/2017 06:27 PM, Eric Ren wrote:
>>
>> Hi!
>>
>> In cluster environment, lvcreate/lvchange may fail to activate logical
>> volumes sometimes.
>>
>> For example:
>>
>> # lvcreate -l100%VG -n lv001 clustermd
>>    Error locking on node a52cbcb: Volume group for uuid not found:
>> SPxo6WiQhEJWDFyeul4gKYX2bNDVEsoXRNfU3fI5TI9Pd3OrIEuIm8jGtElDJzEy
>>    Failed to activate new LV.
>>
>> The log file for this failure is attached. My thoughts on this issue
>> follows, for example on two nodes:
>> n1:
>> ===
>> #lvchange -ay vg/lv1
>> ...
>> clvmd will ask for peer daemon on n2
>> to activate lv1 as well
>>
>> n2:
>> ===
>> lvm need to find lv1 and the PVs for lv1,
>> in device cache which aims to avoid frequent scan all
>> disks. But if the PV(s) might not be available
>> in device cache, it responses n1 with errors....
>>
>> We found that 'clvmd -R' can be a workaround before activating LV, because
>> what "clvmd -R" is to refresh device cache on every node as its commit
>> message said:
>> ===
>> commit 13583874fcbdf1e63239ff943247bf5a21c87862
>> Author: Patrick Caulfield <pcaulfie at redhat.com>
>> Date:   Wed Oct 4 08:22:16 2006 +0000
>>
>>      Add -R switch to clvmd.
>>      This option will instruct all the clvmd daemons in the cluster to
>> reload their device cache
>> ==
>>
>> I think the reason why clvm doesn't refresh device cache every time before
>> activating LV,
>> is to avoid scanning all disks frequently.
>>
>> But, I'm not sure if I understand this issue correctly, will appreciate
>> much if someone can
>> help.
>>
>> Regards,
>> Eric
>>
>>
>>
>>
>> _______________________________________________
>> linux-lvm mailing list
>> linux-lvm at 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 at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/



-- 
  .~.
  /V\
 //  \\
/(   )\
^`~'^