[Linux-HA] Confusion about MailTo RA and monitoring
lmb at suse.de
Mon Jul 16 03:35:57 MDT 2007
On 2007-07-16T11:27:05, Peter Kruse <pk at q-leap.com> wrote:
> This was indeed exactly the answers I was anticipating.
> So, if I'm not forced to specify a monitor action in
> my cib, then I might also not define a monitor action
> for my filesystem resource. Because once it's mounted,
> it's mounted, isn't it? And if another resource
> like apache is running on top of it, it cannot not
> be unmounted anyways. So it really does not make
> any sense to check for the filesystem being mounted
> every monitor interval.
> Makes sense? Even if you don't agree you should accept
> that it would be perfectly legal to do this.
True. You don't need to monitor everything. In theory, monitoring the
top-most service is mostly sufficient.
The Filesystem RA doesn't really check anything which wouldn't be
covered by that. However, there is one exception:
_If_ the fs goes haywire or is forcibly unmounted somehow, _and_ you're
not monitoring it, heartbeat will never detect that error, but instead
restart the application on top. That will fail though (because the fs is
gone), and the node be blacklisted for that resource (start failure) and
then migrated somewhere else. ie, no local restart will be attempted.
> My second question is:
> If I haven't defined a monitor action in my cib
> for a resource, will heartbeat still probe it?
Yes. Probes are mandatory and cannot be bypassed.
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
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