[Pacemaker] i am very confused

Lars Marowsky-Bree lmb at suse.de
Wed Feb 18 12:09:23 EST 2009

On 2009-02-18T17:11:32, Glory Smith <xx2glory at gmail.com> wrote:

> 1) well i guess SBD is bit different thing , it cannot be used for general
> data sharing purpose. i cant store my data on SBD disk and all members of
> cluster can access SBD at same time Please correct me if i am wrong. i am
> new to openais-pacemaker.

The SBD mechanism ensures fencing through the shared disk. It can be
used in combination with N nodes and OCFS2, for example.

See http://www.linux-ha.org/SBD_Fencing

> 2) scsi2reservation is not good as it does not provide persistent
> reservation. a node who is having reservation will loose it after a reboot.
> i want something like persistent reservation (sg_persist) . RHCS provide
> persistent reservation through sg_persist.

Uhm, that's exactly what scsi2reservation calls in the background.
Though usually through a reboot, the other cluster members will have
broken the reservation and restarted the services - after all, fail-over
is the whole point of having an HA cluster.

> 3)well regarding sfex , just saw it's document it seems i can use it for
> general data store purpose.. does the ownership  does not gets effected
> during reboots?

Why would ownership information persist across reboots? That is

SCSI2 reservations don't persist across reboots - the bus reset clears

> 4) do you mean when i need to use any of these three SBD , scsi2reservation
> or sfex i will have to set stonith = disable??  cant i have both resource
> and node fencing together?

SBD is a stonith mechanism, so you must keep stonith-enabled=true.

Sure you can mix them, but if you have node-level fencing, you don't
need resource level fencing any longer.


Teamlead Kernel, SuSE Labs, Research and Development
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)
"Experience is the name everyone gives to their mistakes." -- Oscar Wilde

More information about the Pacemaker mailing list