Date: Mon, 8 Aug 2011 16:54:10 +0200 From: Ferdinand Goldmann <ferdinand.goldmann@jku.at> To: freebsd-net@freebsd.org Subject: Problem using CARP + HAST ... Message-ID: <A369574D-BB1B-4330-80F5-084B7D92CBD0@jku.at>
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Hi!
I am trying to create a common resource pool for a certain application =
using
CARP/HAST as described in [1]. However while testing my setup I ran into =
a
problem which I don't know how to fix or work around:
If I shut down only the carp interface on the master (ifconfig carp0 =
down),
the slave will take note of this, make his carp interface the master and
mount the HAST storage using a script called by devd. Everything fine so =
far. BUT:
If, however, I completely shut down the masters network connection =
(using "shut" on
the switchport), the carp interface on the slave will still switch to =
master.=20
But the script for making the HAST storage primary will just hang =
forever:
root 46841 0.0 0.6 3628 1524 ?? S 4:21PM 0:00.08 /bin/sh =
/opt/bin/carp-hast-switch master
root 47043 0.0 2.6 42228 6580 ?? S 4:22PM 0:00.03 hastd: =
hast0 (secondary) (hastd)
Seemingly, this is because the hastd daemons on master and slave are =
unable to=20
communicate. So the script waits forever for the secondary device to go =
away... :
# Wait for any "hastd secondary" processes to stop
for disk in ${resources}; do
while $( pgrep -lf "hastd: ${disk} \(secondary\)" > /dev/null =
2>&1 ); do
sleep 1
done
Im a bit puzzled. Is there a way for hastd to make himself the master in =
case of a timeout
or such? Because in normal operation, whenever the carp interface fails, =
the underlying=20
infrastructure will most likely be down as well.
Even if I'd connect the two machines over an extra port for hastd,
this problem would still occur if I pull the plug on the master. I =
suppose the
slave making himself the master will lead to a split-brain condition ... =
but is there
any way for hastd to handle this automagically? Because otherwise, it =
won't be much
good for a scenario like the above. :-/
Can anybody shed light on this please?
TIA & best regards,
Ferdinand
[1] http://www.freebsd.org/doc/en/books/handbook/disks-hast.html=
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