Dynamic CPU allocation on Exadata X5-2 with OVM

Hi There,

I had a chance to play a little bit with the latest Exadata X5-2 and OVM and here is something really cool.

I have create two VMs to handle different RDBMS version with 12 vcpu each.


[root@exadbadm01]# xm list

Name             ID      Mem    VCPUs    Stats       Time(s)
domain-0         0      8192        4   r.....      29775.4
exavm11g         2     32768       12   .b....       1548.6
exavm12c         3     32768       12   .b....       2548.4

 

Then from exavm11g, here is what we can see from OS point of view:

[root@exavm11g]# cat /proc/cpuinfo | grep name | wc -l

12

And here is what we can see from Oracle point of view:


[oracle@exavm11g]$ sqlplus / as sysdba

SQL> show parameters cpu_count

NAME                  TYPE        VALUE
--------------------- ----------- -------
cpu_count             integer     12

Now lets change the vcpu count:

[root@exadbadm01]# xm vcpu-set exavm11g 8

[root@exadbadm01]# xm list

Name             ID      Mem    VCPUs    Stats       Time(s)
domain-0         0      8192        4   r.....      30154.1
exavm11g         2     32768        8   .b....       1645.2
exavm12c         3     32768       12   .b....       2645.8

An lets see the result on exavm11g…

[root@exavm11g]# cat /proc/cpuinfo | grep name | wc -l

8

And here is what we can see from Oracle point of view:

[oracle@exavm11g]$ sqlplus / as sysdba

show parameters cpu_count</span>

NAME                  TYPE        VALUE
--------------------- ----------- -------
cpu_count             integer     8

Wouaou! Thats dynamic!!

Interesting thing would be to check what’s going on if we have more instances with instance caging and resource manager in place…

I will check that next week during a customer POC!

Of course, if you want to add more vcpu than what is configured in vm.conf, then you have to restart the vm:-)

Cheers

jko

 

 

 

 

 

 

 

 

 

 

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Jacques

I am Oracle Certified Master 11g & 12c database architect with significant experience in heterogeneous environments, and strong ability to lead complex and critical projects requiring multiple technical implementations. at Trivadis SA

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