[hobbit] Question about using no-cache on rrd for xymon 4.3.0.0.beta-2

[Dominique Frise]

Stewart, Tom L. wrote:
> 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 */
> 
> to
> 
> 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?
> 
>  
> 
> Tom
> 
>  
> 
>  
> 
> ------------------------------------------------------------------------
> 
> *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 
> 4.3.0.0.beta-2
> 
>  
> 
> 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=$BBSERVERLOGS/rrd-status.log hobbitd_rrd --no-cache 
> --extra-tests=cpucisco,ifaload,ifload,vload,wphlstat,wperrors 
> --extra-script=/home/xymon/server/ext/extra-rrd.pl  --rrddir=$BBVAR/rrd
> 
> hobbitlaunch.cfg:       CMD hobbitd_channel --channel=data   
> --log=$BBSERVERLOGS/rrd-data.log hobbitd_rrd  --no-cache 
> --extra-tests=mpstat,zonestat  
> --extra-script=/home/xymon/server/ext/rrd_data.pl --rrddir=$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 
> --extra-script=/home/xymon/server/ext/extra-rrd.pl 
> --rrddir=/home/xymon/data/rrd
> 
> 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 
> --extra-script=/home/xymon/server/ext/rrd_data.pl 
> --rrddir=/home/xymon/data/rrd
> 
> xymon     7672  7635  0 14:26 ?        00:00:07 hobbitd_rrd --no-cache 
> --extra-tests=cpucisco,ifaload,ifload,vload,wphlstat,wperrors 
> --extra-script=/home/xymon/server/ext/extra-rrd.pl 
> --rrddir=/home/xymon/data/rrd
> 
> xymon     7681  7636  0 14:26 ?        00:00:03 hobbitd_rrd --no-cache 
> --extra-tests=mpstat,zonestat 
> --extra-script=/home/xymon/server/ext/rrd_data.pl 
> --rrddir=/home/xymon/data/rrd
> 
>  
> 
> 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,
> 
> Tom
> 
Hi,

--no-cache together with Xymon 4.3.0-beta2 works for us.

We use it for status and channel like this:

hobbitlaunch.cfg:       CMD hobbitd_channel --channel=status 
--log=$BBSERVERLOGS/rrd-status.log hobbitd_rrd --no-cache 
--extra-tests=zfs 
--extra-script=/soft/pub/BB/hobbit/server/ext/rrd-status.sh 
--rrddir=$BBVAR/rrd
hobbitlaunch.cfg:       CMD hobbitd_channel --channel=data 
--log=$BBSERVERLOGS/rrd-data.log hobbitd_rrd --no-cache 
--extra-tests=zone 
--extra-script=/soft/pub/BB/hobbit/server/ext/rrd-data.sh 
--rrddir=$BBVAR/rrd

Dominique