Olivier,

Why don't you try the approach of putting your rrd files in a tmpfs filesystem? This seems to have resolved my rrd problem. At least you can try to see if this resolves your issue and then you know for sure it is related to disk IO. This is what I did:

1. mkdir /usr/local/bbvar/rrd_orig

2. mv /usr/local/bbvar/rrd /usr/local/bbvar/rrd_orig

3. mkdir /usr/local/bbvar/rrd

4. Add the following line to /etc/fstab: tmpfs /usr/local/bbvar/rrd tmpfs mode=755,rw,size=2G 0 0

5. mount /usr/local/bbvar/rrd; chown <id of bb user> /usr/local/bbvar/rrd

6. cp -pr /usr/local/bbvar/rrd_orig/rrd/* /usr/local/bbvar/rrd

7. Start hobbit

If you want to keep this as a permanent solution, then you will need to setup a cronjob to periodically copy the rrd files from the tmpfs filesystem back to disk. This is because if you unmount the tmpfs FS all data will be lost. You can put a line in crontab as shown below to run at 8:30 PM daily:

  30 20 * * *  rsync -av /usr/local/bbvar/rrd /usr/local/bbvar/rrd_orig

Remember that everytime you reboot, you will need to copy the files from disk to the tmpfs filesystem. You can put a line in /etc/rc.local to do this for you.

Hope this helps.

-Naeem

         Olivier Beau                                                  
         <olivier at qalpit.c                                             
         om>                                                        To 
                                   hobbit at hswn.dk                      
         08/22/2005 11:28                                           cc 
         PM                                                            
                                                               Subject 
                                   Re: [hobbit] Re: hobbit_rrd stops   
         Please respond to         working after about 1 hour          
          hobbit at hswn.dk                                               
                                                                       
                                                                       
                                                                       
                                                                       
                                                                       

Hi,

it happened a third time for me this night (3 times in 3 weeks) : syptoms: hobbitd seems to slow down and stops graphing.

i think Naeem and me are hitting a bug.

i've looked closer this night, and i saw that hobbitd_rrd was running at 100% on the cpu it was on; i tried to strace the procees, but strace wouldnt give me any ouptut ! i finally killed hobbitd_rrd, and everything went back to normal. hobbitd.log has : Task rrdstatus terminated, status 1 rrd_status.log has : Worker process died with exit code 1, terminating

during normal running, vmstat shows a i/o wait of 25% my problems happened always at night, exactly at the time legato starts

-> something strange is happening whith hobbitd_rrd when the server is under very heavy i/o..

henrik, could this be a OS issue or more a hobbitd_rrd problem ?

Olivier

Selon Naeem.Maqsud at sybase.com:

Well, as nobody has suggested anything to my problem I guess that I'm the only one having this issue. I have managed to find the root cause. The hobbitd_rrd process was showing to be in "uninterruptible sleep" state most of the time with high iowait associated with the CPU it was running on. I suspected that the problem may be due to disk IO while updating rrds for the 2000 hosts. I created a tmpfs filesystem and copied the rrd directory into it. Since then (48 hours ago) my rrd graphs have been updating continuously. I do however need to write back to disk periodically to avoid loss of data after a reboot.

This is OK as a temporary fix but I would like to have a permanent solution. I would like to hear from other hobbit users who have more than 1000 hosts monitored. What type of servers and disk subsystems are they using? Perhaps my problem is to do with RedHat and Dell server combination. Perhaps I need to stripe over multiple spindles.

-Naeem

         Naeem

         Maqsud/SYBASE

To

         08/18/2005 05:02          hobbit at hswn.dk

         PM

cc

Subject

                                   hobbit_rrd stops working after

                                   about 1 hour

Hi,

I'm testing out hobbit 4.1.1 for possible migration from big brother

(with

bbgen). I suspected scalability issues with BB as my rrd graphs were updated intermittently. However, hobbit is exhibiting similar problems. After about 1 hr of restarting hobbit, the rrd graphs stop updating except for the cpu utilization for the hobbit server itself.

The hobbit server is running RedHat Linux AS 3.0. It has 2 x 2.4 GHz Xeon processors and 1GB of memory. About 800 servers are sending updates to the hobbit server. Another 1200 servers are getting remote tests.

Load average has stayed below 1 most of the time. CPU usage has been low with 75% idle. 4 CPUs show up due to hyperthreading and I've noticed that after the restart of hobbit server, hobbitd_rrd process stays on CPU3 with 100% utilization for the one hour that it is busy.

I hope someone can shed some light on this.

Thanks, Naeem

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-- Olivier Beau

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