[DRBD-user] changing resource names

[Gianni Milo]

/dev/host1/acc-hda is the backing storage device where drbd writes the data
for the resource acc-hda.res .
The type of storage can be any form of raw block device, like for example a
disk partition (/dev/sdd1) or a lvm volume (/dev/vg/lv)...or something else
similar.
In your case /dev/host1/acc-hda represents a lvm logical volume called
"acc-hda" which resides in the volume group "host1".
To verify if this is the case, you can issue "pvs", "vgs", "lvs" . If
"acc-hda" shows up in there, then that's the case...
To rename the logical volume you can use "lvrename" command. Make sure you
bring down the drbd resource first, before doing that. Do this one on the
secondary node first (i.e host2).
Once you rename LV, update drbd resource file with the new name and finally
bring up the resource. You need to update ".res" file on both nodes, but
only the section which refers to the secondary node (host2).
Once resource is up and running, repeat same steps on the primary node
(host1).

Gianni



On Sun, 28 Apr 2019 at 03:13, David <david at kenpro.com.au> wrote:

>
> On 26/4/19 10:52 pm, Roland Kammerer wrote:
>
> On Thu, Apr 25, 2019 at 11:02:55AM +1000, David wrote:
>
> On 24/4/19 5:44 pm, Roland Kammerer wrote:
>
> On Tue, Apr 23, 2019 at 10:22:16PM +1000, David wrote:
>
> Sorry if this is a newbie question.
>
> I have a number of resources (VM's) on a two node system for which the
> resource names are now misleading and I would like to change them. Is it
> possible?
>
> Do I just change the .res files or some other config? Do I have to shutdown
> all VM's and change both node configs at the same time?
>
> I can't find any documentation how to (safely) do it.
>
> Could anybody point me to it?
>
> You created these manually, right? No plugins/drbdmanage/LINSTOR involved?
>
> If so, sure, you can do that. "down" it on one side, rename it in the
> res file, and "up" it again. Check how you used the DRBD block device.
> Via the minor? Good. Via the udev generated symlink? You need to adapt
> your setup.
>
> And again, this is all for a manual setup. All plugins I can imagine/we
> provide would be horribly confused if somebody changes the name
> underneath them.
>
> I have this udev rule:
> KERNEL=="drbd*", IMPORT{program}="/sbin/drbdadm sh-udev minor-%m",
> NAME="$env{DEVICE}", SYMLINK="drbd/by-res/$env{RESOURCE}
> drbd/by-disk/$env{DISK}"
>
> but I admit I have no idea what to do with it :)
>
> Looks okay. So you most likely have some /dev/drbd/by-res/resname/0
> symlinks to to the actual device. And then it depends how DRBD is used.
> Maybe there is a file system on top and it gets mounted as "/dev/drbd123
> /mnt". Then you are fine. But if it got mounted as
> "/dev/drbd/by-res/.... /mnt", then obviously you have to change that
> when you rename the DRBD resource. But you have to know your system.
> "/etc/fstab" is one case where it might be necessary to change the block
> device.
>
> Thanks for your continuing help....
>
> fstab has only the host's root and swap. The guest called "acc" is
> represented thus:
>
> root at hostl1:~# ls -l /dev/drbd/by-res/acc-hda
> lrwxrwxrwx 1 root root 12 Apr 18 15:09 /dev/drbd/by-res/acc-hda ->
> ../../drbd15
>
> root at host1:~# ls -l /dev/drbd/by-disk/host1/acc-hda
> lrwxrwxrwx 1 root root 15 Apr 18 15:09 /dev/drbd/by-disk/host1/acc-hda ->
> ../../../drbd15
>
> root at host1:~# ls -l /dev/drbd15
> brw-rw---T 1 libvirt-qemu libvirt-qemu 147, 15 Apr 27 18:42 /dev/drbd15
> root at host1:/etc/drbd.d# cat acc-hda.res
> resource acc-hda {
>     on host1 {
>         device        /dev/drbd15;
>         disk        /dev/host1/acc-hda;
>         address        169.254.88.21:44535;
>         meta-disk    internal;
>     }
>     on host2 {
>         device        /dev/drbd15;
>         disk        /dev/host2/acc-hda;
>         address        169.254.88.22:44535;
>         meta-disk    internal;
>     }
>
>     net {
>         allow-two-primaries;
>     }
> }
>
> root at host1:~# ls -l /dev/host1/acc-hda
> lrwxrwxrwx 1 root root 8 Apr 18 15:06 /dev/host1/acc-hda -> ../dm-14
>
> Am I right to assume that dm-14 being similar to the minor number (15) is
> coincidence? It's not clear to me how /dev/host1/acc-hda is set up or even
> what it does. Does that come from the udev rule somehow?
>
> The change I need to make is of the form "acc" to "xyz", so the steps that
> make sense to me are:
>
> * edit acc --> xyz in /etc/drbd/acc-hda.res on BOTH hosts
>
> * shutdown xyz guest on both hosts
>
> * reload udev rule on both hosts <# udevadm trigger>
>
> * restart primary guest
>
> Does that look right? I would hate to make changes that cause a crash I
> can't recover from.
>
>
>
>
> Regards, rck
> _______________________________________________
> drbd-user mailing listdrbd-user at lists.linbit.comhttp://lists.linbit.com/mailman/listinfo/drbd-user
>
> --
> David McQuire
> 0418 310312
>
> _______________________________________________
> drbd-user mailing list
> drbd-user at lists.linbit.com
> http://lists.linbit.com/mailman/listinfo/drbd-user
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linbit.com/pipermail/drbd-user/attachments/20190428/3f37539d/attachment.htm>