[linux-lvm] Shared VG, Separate LVs
Indivar Nair
indivar.nair at techterra.in
Wed Nov 22 05:49:48 UTC 2017
Hi Eric,
Answering your queries -
*"Did you check if your active-passive model HA stack can always work
correctly and stably byputting one node into offline state?"*
Yes, it works perfectly while failing over and failing back.
*"I noticed you didn't configure LVM resource agent to manage your VG's
(de)activation task,not sure if it can always work as expect, so have more
exceptional checking :)"*
Strangely the Pacemaker active-passive configuration example
shows VG controlled by Pacemaker, while the active-active one does not. I
have taken the active-active configuration for Pacemaker and created 2 LVs,
then instead of formatting it using the GFS2 clustered filesystem, I used
normal XFS and made sure that it is mounted only on one node at a time.
(lv01 on node 2, lv02 on node2)
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/global_file_system_2/ch-clustsetup-gfs2
I can see the clustered VG and LVs as soon ocf:heartbeat:clvm
is started.
Is there anything I am missing here?
Regards,
Indivar Nair
On Tue, Nov 14, 2017 at 10:22 AM, Eric Ren <zren at suse.com> wrote:
> Had a look at your setup, I have one question:
>
> Did you check if your active-passive model HA stack can always work
> correctly and stably by
> putting one node into offline state?
>
> I noticed you didn't configure LVM resource agent to manage your VG's
> (de)activation task,
> not sure if it can always work as expect, so have more exceptional
> checking :)
>
> Eric
>
> On 11/03/2017 02:38 PM, Indivar Nair wrote:
>
> Hi Eric, All,
>
> Thanks for the input. I have got it working.
>
> Here is what I did -
> ------------------------------------------------------------
> ------------------------------------------------------------
> -------------------------------
> Cluster Setup:
> 2 Nodes with CentOS 7.x: clstr01-nd01, clstr01-nd02
> Common storage array between both nodes (8 shared volumes, presented as
> /dev/mapper/mpatha to /dev/mapper/mpathh)
> 2 Port NICs, bonded (bond0) in each node
>
> Resource group grp_xxx (nd01 preferred) -
> Mount Point: /clstr01-xxx
> Cluster IP: 172.16.0.101/24
>
> Resource group grp_yyy (nd02 preferred) -
> Mount Point: /clstr01-yyy
> Cluster IP: 172.16.0.102/24
>
>
> On both nodes:
> --------------
> Edit /etc/lvm/lvm.conf, and configure 'filter' and 'global_filter'
> parameters to scan only the required (local and shared) devices.
>
> Then run -
> # /sbin/lvmconf --enable-cluster
> Rebuild initramfs -
> # mv /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img-orig
> # dracut -H -f /boot/initramfs-$(uname -r).img $(uname -r)
>
> Reboot both nodes.
> --------------
>
>
>
> After rebooting both nodes, run the following commands on any one node:
> --------------
> # pcs cluster start --all
> # pcs resource create dlm ocf:pacemaker:controld op monitor interval=30s
> on-fail=fence clone interleave=true ordered=true
> # pcs resource create clvmd ocf:heartbeat:clvm op monitor interval=30s
> on-fail=fence clone interleave=true ordered=true
> # pcs constraint order start dlm-clone then clvmd-clone
> # pcs constraint colocation add clvmd-clone with dlm-clone
>
>
> # pvcreate /dev/mapper/mpath{a,b,c,d,e,f,g,h}
> # vgcreate -Ay -cy clstr_vg01 /dev/mapper/mpath{a,b,c,d,e,f,g,h}
> # lvcreate -L 100T -n lv01 clstr_vg01
> # mkfs.xfs /dev/clstr_vg01/lv01
> # lvcreate -L 100T -n lv02 clstr_vg01
> # mkfs.xfs /dev/clstr_vg01/lv02
>
>
> # pcs resource create xxx_mount ocf:heartbeat:Filesystem
> device=/dev/clstr_vg01/lv01 directory=/clstr01-xxx fstype=xfs --group
> xxx_grp --disabled
>
> # pcs resource create xxx_ip_01 ocf:heartbeat:IPaddr2 ip=172.16.0.101
> cidr_netmask=24 nic=bond0:0 op monitor interval=30s --group xxx_grp
> --disabled
>
> # pcs constraint location xxx_grp prefers clstr01-nd01=50
> # pcs constraint order start clvmd-clone then xxx_grp
>
> # pcs resource enable xxx_mount
> # pcs resource enable xxx_ip_01
>
>
> # pcs resource create yyy_mount ocf:heartbeat:Filesystem
> device=/dev/clstr_vg01/lv02 directory=/clstr01-yyy fstype=xfs --group
> yyy_grp --disabled
>
> # pcs resource create yyy_ip_01 ocf:heartbeat:IPaddr2 ip=172.16.0.102
> cidr_netmask=24 nic=bond0:1 op monitor interval=30s --group yyy_grp
> --disabled
>
> # pcs constraint location yyy_grp prefers clstr01-nd02=50
> # pcs constraint order start clvmd-clone then yyy_grp
>
> # pcs resource enable yyy_mount
> # pcs resource enable yyy_ip_01
> --------------
>
>
> # pcs resource show
> --------------
> ------------------------------------------------------------
> ------------------------------------------------------------
> -------------------------------
>
>
> Regards,
>
>
> Indivar Nair
>
> On Mon, Oct 16, 2017 at 8:36 AM, Eric Ren <zren at suse.com> wrote:
>
>> Hi,
>> On 10/13/2017 06:40 PM, Indivar Nair wrote:
>>
>> Thanks Eric,
>>
>> I want to keep a single VG so that I can get the bandwidth (LVM Striping)
>> of all the disks (PVs)
>> PLUS
>> the flexibility to adjust the space allocation between both LVs. Each LV
>> will be used by different departments. With 1 LV on different hosts, I can
>> distribute the Network Bandwidth too.
>> I would also like to take snapshots of each LV before backing up.
>>
>> I have been reading more about CLVM+Pacemaker options.
>> I can see that it is possible to have the same VG activated on multiple
>> hosts for a GFSv2 filesystem.
>> In which case, it is the same PVs, VG and LV getting activated on all
>> hosts.
>>
>>
>> OK! It sounds reasonable.
>>
>>
>> In my case, we will have the same PVs and VG activated on both hosts, but
>> LV1 on Host01 and LV2 on Host02. I paln to use ext4 or XFS filesystems.
>>
>> Is there some possibility that it would work?
>>
>>
>> As said in the last mail, the new resource agent [4] will probably work
>> for you, but I didn't test this case yet. It's easy to have a try - the RA
>> is just shell
>> script, you can just copy LVM-activate to /usr/lib/ocf/resource.d/heartbeat/
>> (assume you've installed resource-agents package), and then configure
>> "clvm + LVM-activate" for pacemaker [5]. Please report back if it doesn't
>> work for you.
>>
>> The LVM-activate RA is WIP. We are thinking if we should merge it into
>> the old LVM RA. So it may changes at any time.
>>
>> [5] https://www.suse.com/documentation/sle-ha-12/book_sleha/
>> data/sec_ha_clvm_config.html
>>
>>
>>
>>
>>> [1] https://github.com/ClusterLabs/resource-agents/blob/master/h
>>> eartbeat/clvm
>>> [2] https://github.com/ClusterLabs/resource-agents/blob/master/h
>>> eartbeat/LVM
>>> [3] https://www.redhat.com/archives/linux-lvm/2017-January/msg00025.html
>>> [4] https://github.com/ClusterLabs/resource-agents/pull/1040\
>>>
>>
>> Eric
>>
>>
>
>
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>
>
>
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