Processors on LPAR Cluster

[MethodMan1972]

Hi All, we have an LPAR cluster with HMC on a P520, and the CPU's are shared among the two configured virtual servers. There are some performance issues on the primary server, and I noticed the CPU's appearing like this:-

proc16 Available 00-16 Processor
proc17 Available 00-17 Processor
proc18 Available 00-18 Processor
proc19 Available 00-19 Processor
proc20 Available 00-20 Processor
proc21 Available 00-21 Processor
proc22 Defined 00-22 Processor
proc23 Defined 00-23 Processor


Proc 22 and 23 in a Defined state. Does this mean that they are in use by the secondary virtual server? (I don't beleive this is the case, as they are partitioned to the primary). Should the system be using these generally, as I am unaware for any reason for these processors to be in a defined state. I am not aware of the history of this server so I am unsure of the reasons, or if this is a fault. How can I find out if this is a fault, and can they be made available easily? Any help or details would be appreciated, thanks.

 

[khalidaaa]

It depends on your profile of the LPAR. They could be assigned to the other LPAR but they could be not! It depends! It seems that those two processors were assigned to this LPAR but then taken off.

The best place to look for this is to open the LPAR's profile and look into the processors tab!

Regards,
Khalid

 

[andy61]

Our p650 running AIX 5.1 with Static LPARS only list the processors belonging to the partition and all show as available. Maybe if the LPAR had previously had them assigned but they now have been moved to another LPAR you could get this conidition. If it is a static LPAR right click on the properties on the partition on HMC and see how many CPUs it should have allocated.

 

[MethodMan1972]

Many thanks for your response, I will check out your suggestions. If I wanted to put monitoring on the CPU / Disk / Mem usage overnight and produce a report in the morning, would the best way to do this be:-

netpmon -o /tmp/netpmon.log -O all

Would this have much of a overhead? Am I better using nmon to do this and what would be the parameters?

Many thanks

 

[khalidaaa]

But why you want to monitor the system? It depends on what you are looking for out of this Monitoring! you can use vmstat, iostat, filemon, svmon! but for all of these, you have to know their usage and why, when you want to use?!?!

Regards,
Khalid

 

[MethodMan1972]

The investigation is two-fold, which is why I wanted to also look at performance along with the Defined Proc's in the LPAR. I ended up writing a script using AIX tools and have some output, which didn't impact the server. So thanks all for you assistance.

 

[p5wizard]

It is not uncommon to have defined processors in an LPAR, especially if you are virtualizing the physical processors into virtual processors and then dynamically altering the CPU settings.

A virtual processor is "hosted" on a physical processor, and you can divide a physical processor in up to 10 virtual processors (e.g. 1ms of CPU time is divided into 10 timeslices of 0.1ms each).

Now on a small machine like a 520 (2 way I guess), it doesn't really make sense to provide an LPAR with more than 2 virtual processor, and as of AIX53 TL3 I believe, AIX is smart enough to ignore the setting and fold the number down to a more appropriate setting - that is, it will only dispatch to the number of virtual processors as there are physical processors in the server. But I digress...

Getting back to the point: When you dynamically alter the number of virtual processors DLPAR-add (and possibly alter the processor entitlement of an LPAR) you add procXX devices, which become "Available". Afterwards, when you DLPAR-remove virtual processors, the are unconfigured and become "Defined"...


HTH,

p5wizard

 

[khalidaaa]

To get more anx perfomance commands and their usage, have a look into this redbook!

http://www.redbooks.ibm.com/abstracts/sg246478.html?Open

Regards,
Khalid