<div dir="ltr">Digimer, thank you very much!<div><br></div><div><span style="font-size:14px">I do not need to have the data accessible on both nodes at once. I want to use the clvm+pacemaker+corosync in OpenStack Cinder.</span><br></div><div><span style="font-size:14px"><br></span></div><div><span style="font-size:14px">then only a VM need access the LV at once. But the Cinder service which runs on the controller node is responsible for snapshotting the LVs which are attaching on the VMs runs on other Compute nodes(such as compute1 node). </span></div><div><span style="font-size:14px"><br></span></div><div><span style="font-size:14px">Need I active the LVs in </span><i style="color:rgb(0,0,0);white-space:pre-wrap">exclusively mode all the time? to supoort snapping it while attaching on the VM.</i></div><div><i style="color:rgb(0,0,0);white-space:pre-wrap"><br></i></div><div><font color="#000000"><span style="white-space:pre-wrap"><i>The following is the result when execute lvscan command on compute1 node:</i></span></font></div><div><font color="#000000"><span style="white-space:pre-wrap"><i><br></i></span></font></div><div><font color="#000000"><i><div style="white-space:pre-wrap">[root@compute1 ~]# lvs</div><div style="white-space:pre-wrap"> LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert</div><div style="white-space:pre-wrap"> volume-1b0ea468-37c8-4b47-a6fa-6cce65b068b5 cinder-volumes -wi------- 1.00g</div><div style="white-space:pre-wrap"><br></div><div style="white-space:pre-wrap"><br></div><div style="white-space:pre-wrap"><br></div><div style="white-space:pre-wrap">and on the controller node:</div><div style="white-space:pre-wrap"><br></div><div><span style="white-space:pre-wrap">[root@controller ~]# lvscan
ACTIVE '/dev/cinder-volumes/volume-1b0ea468-37c8-4b47-a6fa-6cce65b068b5' [1.00 GiB] inherit</span><br></div><div><span style="white-space:pre-wrap"><br></span></div><div><span style="white-space:pre-wrap"><br></span></div><div><span style="white-space:pre-wrap"><br></span></div><div><span style="white-space:pre-wrap">thank you very much!</span></div></i></font></div><div><font color="#000000"><span style="white-space:pre-wrap"><i><br></i></span></font></div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-12-06 11:15 GMT+08:00 Digimer <span dir="ltr"><<a href="mailto:lists@alteeve.ca" target="_blank">lists@alteeve.ca</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 05/12/16 09:10 PM, su liu wrote:<br>
> Thanks for your replay, This snapshot factor will seriously affect my<br>
> application.<br>
<br>
</span>Do you really need to have the data accessible on both nodes at once? To<br>
do this requires a cluster file system as well, like gfs2. These all<br>
require cluster locking (DLM) which is slow compared to normal file<br>
systems. It also adds a lot of complexity.<br>
<br>
In my experience, most people who start thinking they want concurrent<br>
access don't really need it, and that makes things a lot simpler.<br>
<span class=""><br>
> then, because now I have not a stonith device and I want to verify the<br>
> basic process of snapshot a clustered LV.<br>
<br>
</span>Working stonith *is* part of basic process. It is integral to testing<br>
failure and recovery. So it should be a high priority, even in a proof<br>
of concept/test environment.<br>
<div><div class="h5"><br>
> I have a more question:<br>
><br>
> After I create a VG: cinder-volumes on controller node, I can see it<br>
> throuth vgs command on both controller and compute<br>
> 1 nodes. then i create a<br>
> LV:volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5. Then I execute the lvs<br>
> command on both nodes:<br>
><br>
> [root@controller ~]# lvs<br>
> LV VG Attr<br>
> LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert<br>
> volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5 cinder-volumes<br>
> -wi-a----- 1.00g<br>
> [root@controller ~]#<br>
> [root@controller ~]#<br>
> [root@controller ~]#<br>
> [root@controller ~]# ll /dev/cinder-volumes/<br>
> total 0<br>
> lrwxrwxrwx 1 root root 7 Dec 5 21:29<br>
> volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5 -> ../dm-0<br>
><br>
><br>
><br>
> [root@compute1 ~]# lvs<br>
> LV VG Attr<br>
> LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert<br>
> volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5 cinder-volumes<br>
> -wi------- 1.00g<br>
> [root@compute1 ~]#<br>
> [root@compute1 ~]#<br>
> [root@compute1 ~]# ll /dev/cinder-volumes<br>
> ls: cannot access /dev/cinder-volumes: No such file or directory<br>
> [root@compute1 ~]#<br>
><br>
><br>
><br>
> But it seems that the LV can't be exist on the compute1 node. My<br>
> question is that how to access the LV on the compute1 node?<br>
><br>
> thanks very much!<br>
<br>
</div></div>Do you see it after 'lvscan'? You should see it on both nodes at the<br>
same time as soon as it is created, *if* things are working properly. It<br>
is possible, without stonith, that they are not.<br>
<br>
Please configure and test stonith, and see if the problem remains. If it<br>
does, tail the system logs on both nodes, create the LV on the<br>
controller and report back what log messages show up.<br>
<br>
digimer<br>
<span class=""><br>
><br>
> 2016-12-06 9:26 GMT+08:00 Digimer <<a href="mailto:lists@alteeve.ca">lists@alteeve.ca</a><br>
</span>> <mailto:<a href="mailto:lists@alteeve.ca">lists@alteeve.ca</a>>>:<br>
<div><div class="h5">><br>
> On 05/12/16 08:16 PM, su liu wrote:<br>
> > *Hi all,<br>
> ><br>
> > *<br>
> > *I am new to pacemaker and I have some questions about the clvmd +<br>
> > pacemaker + corosync. I wish you could explain it for me if you are<br>
> > free. thank you very much!<br>
> ><br>
> > *<br>
> > *I have 2 nodes and the pacemaker's status is as follows:*<br>
> ><br>
> > [root@controller ~]# pcs status --full<br>
> > Cluster name: mycluster<br>
> > Last updated: Mon Dec 5 18:15:12 2016 Last change: Fri<br>
> Dec 2<br>
> > 15:01:03 2016 by root via cibadmin on compute1<br>
> > Stack: corosync<br>
> > Current DC: compute1 (2) (version 1.1.13-10.el7_2.4-44eb2dd) -<br>
> partition<br>
> > with quorum<br>
> > 2 nodes and 4 resources configured<br>
> ><br>
> > Online: [ compute1 (2) controller (1) ]<br>
> ><br>
> > Full list of resources:<br>
> ><br>
> > Clone Set: dlm-clone [dlm]<br>
> > dlm (ocf::pacemaker:controld): Started compute1<br>
> > dlm (ocf::pacemaker:controld): Started controller<br>
> > Started: [ compute1 controller ]<br>
> > Clone Set: clvmd-clone [clvmd]<br>
> > clvmd (ocf::heartbeat:clvm): Started compute1<br>
> > clvmd (ocf::heartbeat:clvm): Started controller<br>
> > Started: [ compute1 controller ]<br>
> ><br>
> > Node Attributes:<br>
> > * Node compute1 (2):<br>
> > * Node controller (1):<br>
> ><br>
> > Migration Summary:<br>
> > * Node compute1 (2):<br>
> > * Node controller (1):<br>
> ><br>
> > PCSD Status:<br>
> > controller: Online<br>
> > compute1: Online<br>
> ><br>
> > Daemon Status:<br>
> > corosync: active/disabled<br>
> > pacemaker: active/disabled<br>
> > pcsd: active/enabled<br>
> > *<br>
> > *<br>
><br>
> You need to configure and enable (and test!) stonith. This is<br>
> doubly-so<br>
> with clustered LVM/shared storage.<br>
><br>
> > *I create a lvm on controller node and it can be seen on the<br>
> compute1<br>
> > node immediately with 'lvs' command. but the lvm it not activate on<br>
> > compute1.<br>
> ><br>
> > *<br>
> > *then i want to create a snapshot of the lvm, but failed with<br>
> the error<br>
> > message:*<br>
> ><br>
> > /### volume-4fad87bb-3d4c-4a96-<wbr>bef1-8799980050d1 must be active<br>
> > exclusively to create snapshot ###<br>
> ><br>
> > /<br>
> > *Can someone tell me how to snapshot a lvm in the cluster lvm<br>
> > environment？ thank you very much。*<br>
><br>
> This is how it works. You can't snapshot a clustered LV, as the error<br>
> indicates. The process is ACTIVE -> deactivate on all node -> set<br>
> exclusive on one node -> set it back to ACTIVE, then you can snapshot.<br>
><br>
> It's not very practical, unfortunately.<br>
><br>
> > Additional information:<br>
> ><br>
> > [root@controller ~]# vgdisplay<br>
> > --- Volume group ---<br>
> > VG Name cinder-volumes<br>
> > System ID<br>
> > Format lvm2<br>
> > Metadata Areas 1<br>
> > Metadata Sequence No 19<br>
> > VG Access read/write<br>
> > VG Status resizable<br>
> > Clustered yes<br>
> > Shared no<br>
> > MAX LV 0<br>
> > Cur LV 1<br>
> > Open LV 0<br>
> > Max PV 0<br>
> > Cur PV 1<br>
> > Act PV 1<br>
> > VG Size 1000.00 GiB<br>
> > PE Size 4.00 MiB<br>
> > Total PE 255999<br>
> > Alloc PE / Size 256 / 1.00 GiB<br>
> > Free PE / Size 255743 / 999.00 GiB<br>
> > VG UUID aLamHi-mMcI-2NsC-Spjm-QWZr-<wbr>MzHx-pPYSTt<br>
> ><br>
> > [root@controller ~]# rpm -qa |grep pacem<br>
> > pacemaker-cli-1.1.13-10.el7_2.<wbr>4.x86_64<br>
> > pacemaker-libs-1.1.13-10.el7_<wbr>2.4.x86_64<br>
> > pacemaker-1.1.13-10.el7_2.4.<wbr>x86_64<br>
> > pacemaker-cluster-libs-1.1.13-<wbr>10.el7_2.4.x86_64<br>
> ><br>
> ><br>
> > [root@controller ~]# lvs<br>
> > LV VG Attr<br>
> > LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert<br>
> > volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5 cinder-volumes<br>
> -wi-a-----<br>
> > 1.00g<br>
> ><br>
> ><br>
> > [root@compute1 ~]# lvs<br>
> > LV VG Attr<br>
> > LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert<br>
> > volume-1b0ea468-37c8-4b47-<wbr>a6fa-6cce65b068b5 cinder-volumes<br>
> -wi-------<br>
> > 1.00g<br>
> ><br>
> ><br>
> > thank you very much!<br>
> ><br>
> ><br>
> ><br>
> ><br>
> ><br>
> > ______________________________<wbr>_________________<br>
> > Users mailing list: <a href="mailto:Users@clusterlabs.org">Users@clusterlabs.org</a><br>
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> ><br>
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> ><br>
><br>
><br>
> --<br>
> Digimer<br>
> Papers and Projects: <a href="https://alteeve.ca/w/" rel="noreferrer" target="_blank">https://alteeve.ca/w/</a><br>
> What if the cure for cancer is trapped in the mind of a person without<br>
> access to education?<br>
><br>
> ______________________________<wbr>_________________<br>
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<br>
<br>
--<br>
Digimer<br>
Papers and Projects: <a href="https://alteeve.ca/w/" rel="noreferrer" target="_blank">https://alteeve.ca/w/</a><br>
What if the cure for cancer is trapped in the mind of a person without access to education?<br>
<br>
<br>
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</div></div></blockquote></div><br></div>