[Linux-cluster] Help with a two node cluster for a web serverneeded

[Holger L. Ratzel]

Hi,

Am Montag 14 Januar 2008 21:03:46 schrieb Lon Hohberger:
> So, what was happening was this:
[...]
>
> First, let's ping the router with the cable unplugged to see how long it
> takes for our heuristic to complete when things are "broken".  On my
> machine:
>
> [lhh at ayanami ~]$ time ping -c1 -t1 frederick
> PING frederick (12.1.2.99) 56(84) bytes of data.
>
> >From ayanami (12.1.2.37) icmp_seq=1 Destination Host Unreachable
>
> --- frederick ping statistics ---
> 1 packets transmitted, 0 received, +1 errors, 100% packet loss, time 0ms
>
>
> real    0m3.006s
> ^^^^^^^^^^^^^^^^
> user    0m0.000s
> sys     0m0.000s
>

[root at testcluster-1 cluster]# time ping -c3 -t1 10.200.10.1
PING 10.200.10.1 (10.200.10.1) 56(84) bytes of data.
64 bytes from 10.200.10.1: icmp_seq=1 ttl=64 time=1.41 ms
64 bytes from 10.200.10.1: icmp_seq=2 ttl=64 time=1.29 ms
64 bytes from 10.200.10.1: icmp_seq=3 ttl=64 time=1.32 ms

--- 10.200.10.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2001ms
rtt min/avg/max/mdev = 1.290/1.341/1.410/0.065 ms

real    0m2.007s
^^^^^^^^^^^^^^^^
user    0m0.001s
sys     0m0.002s
[root at testcluster-1 cluster]# time ping -c3 -t1 10.200.10.65
PING 10.200.10.65 (10.200.10.65) 56(84) bytes of data.
From 10.200.10.187 icmp_seq=1 Destination Host Unreachable
From 10.200.10.187 icmp_seq=2 Destination Host Unreachable
From 10.200.10.187 icmp_seq=3 Destination Host Unreachable

--- 10.200.10.65 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 1999ms
, pipe 3

real    0m3.004s
^^^^^^^^^^^^^^^^
user    0m0.001s
sys     0m0.002s

[...]
>
> Option 1:
>
> Make 1 tko sufficient by making the heuristic do more work.  In my quick
> testing, the same 3 seconds for 1 packet was used for 3 packets.
>
[...]
>
> Option 2:
>
> Make things fit around your heuristic.  Given our 12 second "negative"
> case for our heuristic/tko, we can simply make qdisk time out in >12
> seconds.  Then, we double that and add a bit for CMAN:

First I've tried both options, but with no success. Then I've tried to do 
both, to be on the safe side:

        ...
        <quorumd interval="1" label="Qdisk1" tko="15" votes="1">
                <heuristic interval="1" program="ping 10.200.10.1 -c3 -t1" 
score="1" tko="1"/>
        </quorumd>
        <totem token="40000"/>
        ...

Then I watched what happend by running 'clustat -li 1' on node 1. After that I 
unpluged the cable from node 1. After about 45 seconds node 2 was reported 
dead by clustat, but the quorum disk was still reported online. And then 
about 10 seconds later both nodes fenced each other...

I've attached parts of '/var/log/messages' from both nodes. Perhaps it 
contains helpfull information.

Many thanks and best regards,

	Holger

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