Sending messages.

[Bernard Frit]

At 10:29 17/10/01 +0200, you wrote:

>What about STONITH? This is absolutely necessary if you use shared disks
>(which I assume you do - or what else do you mean with 'mirrored via
>scsi'?).

The disks are not supposed to be shared even though that's
a possible condition. Machine_A is mirrored on a machine_B
volume through a cross scsi link. The mirror volume
is not supposed to be mounted (even readonly) on machine_B.

I'not sure I fully understand what STONITH can really do.
As far as I understand STONITH can remotedly switch off
a machine using some specific device but not only stop heartbeat.

So far, we cannot have any specific power device for these two
machines only. All our servers are plugged on the same
protected power line.

>Also I would do the monitoring on machine_B via mon and tell mon to stop
>the local Heartbeat if it detects problems with the disk.

I planned to monitor the production disks but not the
backup disks as they are not supposed to be localy mounted.

Here is a quick outline of the cluster.

Machine A                               Machine B
--------------------------------------------------------------

+--------+                              +--------+
| scsi 0 |                             | scsi 0 |
+--------+                             +--------+
         |                                       |
    +-------+                               +-------+
    | HD    |                               | HD    |
    | SCSI  |          system disk         | SCSI  |
    | SYST  |                               | SYST  |
    +-------+                                +-------+

+--------+                              +--------+
| scsi 1 |                              | scsi 1 |
+--------+                              +--------+
         |                                       |
    +-------+                               +-------+
    | HD    |                               | HD    |
    | SCSI  |                               | SCSI  |
    | PROD  |  SMB                     HTTP | PROD  |
    +-------+                                +-------+

             X                       X
            /                          \
+--------+/                            \+--------+
| scsi 2 |-----------+     +------------| scsi 2 |
+--------+           |     |            +--------+
                  +---)-----+
+--------+       |   |                  +--------+
| scsi 3 |-------+   +------------------| scsi 3 |
+--------+                              +--------+
         |                                       |
    +-------+                               +-------+
    | HD    |                               | HD    |
    | SCSI  |                               | SCSI  |
    | MIRR  |   HTTP                  SMB  | MIRR  |
    +-------+                                +-------+

Each machine has 4 scsi interfaces and 3 groups of
scsi disks.

Each back up disk (MIRR) is only mounted (rw) by the
opposite machine.

Thanks for your help. Regards.
--
Bernard FRIT