[DRBD-user] drbd storage for Oracle VM

Dan Barker dbarker at visioncomm.net
Wed Apr 4 14:57:52 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

>>>>> Eduardo, thank you for your input, but Virtual Box (workstation
>>>>> product) is a completely different animal than Oracle VM (bare-metal
>>>>> hypervisor). I don't get to choose the underlying storage, and OVM3
choses OCFS2.
>>>>> I guess I'll simply have to try it out and see if DRBD will

>>>> It will. However OCFS2 will only work on Protocol C (dual-Primary
>>>> mode requires synchronous replication by definition), so your
>>>> original plan of using protocol A or B is out.
>>>> Why do you need to compile though? I thought UEK2 shipped with DRBD.
>>>> Or has that not been made available for Oracle VM yet?
>>>> Florian

>>> That sounds encouraging. Not having to compile will mean I don't have to
locate all the dependencies.
>>> "UEK2 shipped with DRBD." How would I check?

>> "modinfo drbd; which drbdadm", or yum search drbd.

> I had already tried drbdadm --help and got "command not found". Modinfo
came up with "could not find module drbd". yum requires a repository to do
anything. I tried
http://public-yum.oracle.com/repo/OracleLinux/OL5/latest/x86_64/ but drbd
wasn't there. So I tried to compile. I found gcc, make and flex, but am
coming up empty on linux-headers- I don't believe I can
build a drbd without the headers. Any ideas? (I also posted the question on
the Oracle VM forum at forums.oracle.com)

> My commands:
> ./configure --with-km --prefix /usr --sysconfdir /etc --localstatedir /var
> make clean all

> Result:
>  Userland tools build was successful.
>  SORRY, kernel makefile not found.
>  You need to tell me a correct KDIR,
>  Or install the neccessary kernel source packages.

> (as expected). Any ideas on finding kernel headers?

>>> I have no need for dual-primary and I can't see how OCFS2 can even tell
if the underlying block device is dual-primary or single-primary.

>> Because the device wouldn't be writable on one of the nodes, which
>> OCFS2 is sure to choke on?

> Well, before a failure, xen won't even be running. I don't kwow if OCFS2
will need write permissions on a volume not mounted. I'd expect not. The
stand-by node will bring up drbd secondary and xen not at all. Failover will
include assuring the primary node is down or at least offline, 'drbdadm
primary r0' at the warm site, and then start xen (which will mount the OCFS2
volume as part of its initialization - at least that's what I'm guessing
will work. I can't test it until I can get the kernel modules compiled.

>>> I believe Eduardo was using dual-primary. I simply need to do a
warm-failover (manual) in the event of a disaster.

>> Probably need to do OCFS2-on-iSCSI with iSCSI-on-DRBD then.
>> Florian

> I don't see the need for that level of complexity. Before we'd do that
many levels of 
> misdirection on a single host (SAS/Raid/DRBD/IET/OVM/OCFS2), I think a SAN
would be a 
> better choice. My goal is to get this running in a single box (per site).

I got an answer from forums.oracle.com. There is a development platform for
this sort of thing. Since I heard nothing from the DRBD community, I'll
assume I'm in new territory. I'll report back after I build a drbd kernel
rpm (or the 3.1.1 Oracle VM comes out with drbd built in - it's to use the
new UEK2 kernel).

REF: https://forums.oracle.com/forums/thread.jspa?threadID=2368799

More information about the drbd-user mailing list