Ocfs2 devel - May 2019 - OCFS2 with global heartbeat on DRBD devices

Hi,

I'm wondering why the current version of the "o2cb" tool does not
support global heartbeat on DRBD devices.

Do I misunderstand the feature "global heartbeat" in that I should not
use it on DRBD at all?

I patched the "o2cb" tool to recognize DRBD devices for starting a
global heartbeat. Now the global heartbeat configuration with DRBD seems to work
at cluster start, but I wonder whether it really is that easy - or I am just
missing something. Maybe it failed silently and I did not notice?

BTW I edited file "o2cb_scandisk.c" function "add_to_list()"
like this:

                                               if (!add)
                                                               add =
!strncmp(path->path, "/dev/rbd", 8);
                                               if (!add) // added
                                                               add =
!strncmp(path->path, "/dev/drbd", 9); // added

and by observing the output of "/proc/drbd" I can tell that the stats
for data read and data written on the DRBD device for the global heartbeat
increases, while it stays the same on all other DRBD devices. (I have not
mounted any of these volumes)

To me it looks like it works. Can anybody comment? Can I somehow
"observe" the proper operation of the global heartbeat?

Regards,

Daniel

-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://oss.oracle.com/pipermail/ocfs2-devel/attachments/20190503/9493557a/attachment.html

Cc ocfs2-tools-devel.

Hi Daniel,
I don't have experience on using global heartbeat on DRBD device.
But from my understanding, I don't think there is any restriction for this
use case.

Thanks,
Joseph

On 19/5/3 20:54, Daniel Sobe wrote:
> Hi,
> 
> I'm wondering why the current version of the "o2cb" tool does
not support global heartbeat on DRBD devices.
> 
> Do I misunderstand the feature "global heartbeat" in that I
should not use it on DRBD at all?
> 
> I patched the "o2cb" tool to recognize DRBD devices for starting
a global heartbeat. Now the global heartbeat configuration with DRBD seems to
work at cluster start, but I wonder whether it really is that easy - or I am
just missing something. Maybe it failed silently and I did not notice?
> 
> BTW I edited file "o2cb_scandisk.c" function
"add_to_list()" like this:
> 
>                                                if (!add)
>                                                                add =
!strncmp(path->path, "/dev/rbd", 8);
>                                                if (!add) // added
>                                                                add =
!strncmp(path->path, "/dev/drbd", 9); // added
> 
> and by observing the output of "/proc/drbd" I can tell that the
stats for data read and data written on the DRBD device for the global heartbeat
increases, while it stays the same on all other DRBD devices. (I have not
mounted any of these volumes)
> 
> To me it looks like it works. Can anybody comment? Can I somehow
"observe" the proper operation of the global heartbeat?
> 
> Regards,
> 
> Daniel
> 
> 
> 
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel at oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>