On Oct 28, 2010, at 2:04 PM, Justin Greenfield wrote:
> No, that wasn't it. When the 10.5.8 update came out I was hopeful that it
> addressed our problem, but it did not.
Richard and Justin,
I encountered the problem early in 2008 when I first set up the LDM under OS X
v10.5. Steve Emmerson, Tom Yoksas, and Mike Schmidt at Unidata spend a fair bit
of time poking around in my system trying to get to the root of the problem,
and they managed to reproduce it on their own system as well. They concluded
that it was an OS X bug involving calls to fcntl, as Justin noted, and they
submitted a bug report, probably in mid-2008. They revisited the problem in
spring of 2009 but the bug was still there, as I discovered when upgrading to
Snow Leopard and as Justin also noted.
Like Justin, I developed a script that tries to compensate for the problem, in
my case by checking (every half an hour) for the existence of data that streams
in frequently, and if the data are missing, assuming that this is evidence of
the problem, killing the LDM's rpc processes, running pqcat and pqcheck, and
restarting the LDM. WIth some refinements, this seems to have been working most
of the time for the last two years, with only occasionally (a couple of times a
year, maybe) needing me to intervene manually. (I don't think I've ever had to
go so far as reboot the system due solely to this particular problem with the
LDM.)
For our purposes, this kludge has worked well enough. I can imagine that some
operations need to receive data with a very high level of reliability, but for
us, there are other sources of data disruption that are generally more
significant (and even those aren't too bad).
-- Dave
****************************************************************
* | __ __ \|/ *
* Dr. Dave Dempsey | ) ^ /|| ||\ --0-- *
* Dept. of Geosciences |) ) ^ / ||_|| \ /|\ *
* San Francisco State University | ) ) / | _ | \ *
* 1600 Holloway Ave. |) )/ || || \ *
* San Francisco, CA 94132 | ) ) ||_|| \ *
* |) ) ) | _ | \ *
* Phone: (415) 338-7716 | ) ) || || \ *
* FAX: (415) 338-7705 |) ) )~~~~~~~~~~~~~~~*
* Email: ddempsey@xxxxxxxxxxxxxxx | ) ) ) ~ ~ ~ ~ *
* |) ) ) ) ~ ~ ~ *
****************************************************************
