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

[emmanuel segura]

But When I say any command, I mean "any clvmd -R", I used clvmd with
redhat 5.8(rhcs) and I never used clvmd -R when the devices changed,
only on the old redhat version.

2017-04-20 10:45 GMT+02:00 Eric Ren <zren at suse.com>:
> Hi!
> On 04/20/2017 04:29 PM, emmanuel segura wrote:
>>
>> 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.
>
> Thanks for your reply! Yes, I don't need to execute any command on any
> remote node. But, in such case, we need "clvmd -R" on one of the nodes.
>
> BTW, my versions:
> lvm2-clvm-2.02.120-72.8.x86_64
> lvm2-2.02.120-72.8.x86_64
>
> Regards,
> Eric
>
>>
>> 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/
>>
>>
>>
>
> _______________________________________________
> 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/



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