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Quick question regarding wiki vs 'Clusters from Scratch v2'

 

 

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m+pacemaker at nerdish

Aug 1, 2012, 4:20 PM

Post #1 of 2 (262 views)
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Quick question regarding wiki vs 'Clusters from Scratch v2'

Good afternoon,

Looking at the corosync configuration examples on the wiki (
http://www.clusterlabs.org/wiki/Initial_Configuration ) and in the Clusters
from Scratch document (
http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Clusters_from_Scratch/_sample_corosync_configuration.html),
there are a number of changes or omissions of settings.

The wiki example includes:

token: 5000
token_retransmits_before_loss_const: 20
join: 1000
consensus: 7500
vsftype: none
max_messages: 20
clear_nod_high_bit: yes

... and a few other settings that are no longer in the CfSv2 document. The
corosync.conf example there is very close to the default configuration when
building from source. It no longer covers creating a service definition in
/etc/corosync/services.d/, because that's no longer needed and instead
corosync and pacemaker are started individually. What about the other
settings, though? I noticed with the CfSv2 sample config only (altered for
my network), I get negative node ids since it doesn't include the
'clear_node_high_bit' setting. Does that have no negative repercussions
with pacemaker? Are any of those other more conservative timing settings
still relevant, or is it pretty safe to just tweak the example
configuration and let corosync and pacemaker do their thing with largely
default values?

Thanks,
Mark


andrew at beekhof

Aug 5, 2012, 9:53 PM

Post #2 of 2 (246 views)
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Re: Quick question regarding wiki vs 'Clusters from Scratch v2' [In reply to]

On Thu, Aug 2, 2012 at 9:20 AM, mark - pacemaker list
<m+pacemaker [at] nerdish> wrote:
> Good afternoon,
>
> Looking at the corosync configuration examples on the wiki (
> http://www.clusterlabs.org/wiki/Initial_Configuration ) and in the Clusters
> from Scratch document (
> http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Clusters_from_Scratch/_sample_corosync_configuration.html
> ), there are a number of changes or omissions of settings.
>
> The wiki example includes:
>
> token: 5000
> token_retransmits_before_loss_const: 20
> join: 1000
> consensus: 7500
> vsftype: none
> max_messages: 20
> clear_nod_high_bit: yes
>
> ... and a few other settings that are no longer in the CfSv2 document. The
> corosync.conf example there is very close to the default configuration when
> building from source. It no longer covers creating a service definition in
> /etc/corosync/services.d/, because that's no longer needed and instead
> corosync and pacemaker are started individually. What about the other
> settings, though? I noticed with the CfSv2 sample config only (altered for
> my network), I get negative node ids since it doesn't include the
> 'clear_node_high_bit' setting. Does that have no negative repercussions
> with pacemaker?

Pacemaker uses uint32_t for storing the nodeid, so no it doesn't care.
It does make the logs annoying though since not everyone uses %u
everywhere (which correctly interprets the first bit to NOT indicate a
negative number).
And if you're using OCFS2 and possibly GFS2, its still a good idea.

> Are any of those other more conservative timing settings
> still relevant, or is it pretty safe to just tweak the example configuration
> and let corosync and pacemaker do their thing with largely default values?

Pretty much.
The conservative timings came from a time when I was running clusters
with 8+ nodes.
Most people aren't doing that and its a few less things for admins to
think about :)

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