R: [Linux-cluster] High system CPU usage in one of a two node cluster

Marco Lusini marco.lusini at governo.it
Fri Jan 5 09:38:41 UTC 2007


> 
> System load averages are the average of the number of 
> processes on the run queue over the past 1, 5, and 15 
> minutes.  It doesn't generally trend upwards over time; if 
> that were the case, I'd be in trouble:
>

I am in trouble, then :-)

As I told in the first mail, as system (i.e. kernel) CPU 
usage grows so does the system load (1, 5, and 15 mins average).
In order to better show what I see in my clusters, I am sending
more graphs (on a yearly time base) that illustrate how system load 
trends upwards as kernel usage grows.
Graphs were produced by CACTI probing the snmpd daemon running on the nodes.

Again note how the trend swap from node to node on reboots.

> 
> However, it is a little odd that you had 10 hours of runtime 
> for clurgmgrd and over 6 for dlm_recvd.  Just taking a wild 
> guess, but it looks like the locks were all mastered on frascati.
>

How can I get more info on this? I checked /proc/cluster/dlm_locks
on both nodes and it is empty.
Here is the output of cat /proc/cluster/dlm_stats:

  [root at estestest ~]# cat /proc/cluster/dlm_stats
  DLM stats (HZ=1000)

  Lock operations:    1688738
  Unlock operations:   838064
  Convert operations:       0
  Completion ASTs:    2526802
  Blocking ASTs:            0

  Lockqueue        num  waittime   ave

  [root at frascati ~]# cat /proc/cluster/dlm_stats
  DLM stats (HZ=1000)

  Lock operations:    1122141
  Unlock operations:   556623
  Convert operations:       0
  Completion ASTs:    1678764
  Blocking ASTs:            0

  Lockqueue        num  waittime   ave
  WAIT_RSB           6         3     0
  WAIT_GRANT    1122141   32507056    28
  WAIT_UNLOCK   556623    316924     0
  Total         1678770   32823983    19

>
> How many services are you running?
> 

At the moment I have 3 services on estestest (Sybase SQL server, a tomcat5 
application and an apache web site) and 2 services on frascati (another
tomcat5 application and Postgres SQL server).

> Also, take a look at:
> 
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=212634
> 
> The RPMs there might solve the problem with dlm_recvd.  
> Rgmanager in some situations causes a strange leak of NL 
> locks in the DLM.  If dlm_recvd has to traverse lock lists 
> and that list is ever-growing (total speculation here), it 
> could explain the amount of consumed system time.
> 

If I use those RPMs, will the patches be included in RHCS 4.5
(I think so, but just to be sure...)?

Thanks,

Marco



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