[hobbit] Question about using no-cache on rrd for xymon

Stewart, Tom L. Tom.Stewart at landsend.com
Thu Nov 19 16:47:41 CET 2009

It has been almost a week and no-one has answered my question about
turning off caching in the latest xymon code 


I checked the source code and my -no-cache flag seems to be correct, but
the caching is continuing and is causing holes ( no update for a five
minute period) in the rrd files. I also found where -no-cache is set
within do_rrd.c and hobbitd_rrd.c, so I am assuming that there is a bug
here that does not turn off caching using the -no-cache flag. 


So for a temporary fix, can I just set:

do_rrd.c:int use_rrd_cache = 1;   /* Use the cache by default */


do_rrd.c:int use_rrd_cache = 0;    /* Don't use the cache by default */


recompile and move the binary over or would I be wasting my time as the
caching would still continue?






From: Stewart, Tom L. [mailto:Tom.Stewart at landsend.com] 
Sent: Friday, November 13, 2009 3:19 PM
To: hobbit at hswn.dk
Subject: [hobbit] Question about using no-cache on rrd for xymon


We are having issues with rrd leaving 5-10 minute intervals of no data
for items such as cpu load on various systems. Most of the time it
happens three times in a row like at 2, 3 and 4 pm. I am not finding
anything is the logs on either the client or server. Some googling
indicated that the issue may go away by using the no-cache option for
RRD. I have added it to the hobbitlaunch.cfg as such:


hobbitlaunch.cfg:       CMD hobbitd_channel --channel=status
--log=$BBSERVERLOGS/rrd-status.log hobbitd_rrd --no-cache
--extra-script=/home/xymon/server/ext/extra-rrd.pl  --rrddir=$BBVAR/rrd

hobbitlaunch.cfg:       CMD hobbitd_channel --channel=data
--log=$BBSERVERLOGS/rrd-data.log hobbitd_rrd  --no-cache
--extra-script=/home/xymon/server/ext/rrd_data.pl --rrddir=$BBVAR/rrd


This is on a 32 bit red hat system and when I do a ps -ef | grep rrd I
show the following:


xymon     7635  7599  0 14:26 ?        00:00:01 hobbitd_channel
--channel=status --log=/home/xymon/logs/rrd-status.log hobbitd_rrd
--no-cache --extra-tests=cpucisco,ifaload,ifload,vload,wphlstat,wperrors

xymon     7636  7599  0 14:26 ?        00:00:00 hobbitd_channel
--channel=data --log=/home/xymon/logs/rrd-data.log hobbitd_rrd
--no-cache --extra-tests=mpstat,zonestat

xymon     7672  7635  0 14:26 ?        00:00:07 hobbitd_rrd --no-cache

xymon     7681  7636  0 14:26 ?        00:00:03 hobbitd_rrd --no-cache


So it looks like it is in effect, but looking at the tmp file I still
see the following:


srw-rw-rw- 1 xymon xymon        0 Nov 13 14:26 rrdctl.7672

srw-rw-rw- 1 xymon xymon        0 Nov 13 14:26 rrdctl.7681


When I stop and restart xymon I still get messages such as:


rrd-status.log:2009-11-13 14:26:09 Cache flush completed

rrd-status.log:2009-11-13 14:26:18 Peer not up, flushing message queue


So my question is have I placed the -no-cache in the wrong sequence on
the startup command or is that been taken out of beta-2?


Thank you,


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.xymon.com/pipermail/xymon/attachments/20091119/01731de2/attachment.html>

More information about the Xymon mailing list