Oracle Database Appliance X5-2
 

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Memory / DIMM upgrades are now possible for the X4-2, X5-2 and newer versions. OS kernel parameters should be altered to take advantage of this increased memory. You may find that after patching that the kernel parameter changes revert back to the original memory configuration. This is identified as  Bug 25192165. The temporary fix is to manually update the kernel parameter back to the previous values. This note will also provide recommendations for X5-2 using either 768G or 512G per server compared to the base 256G.

Applies to:

Symptoms

Kernel parameters are incorrect after upgrading / patching the ODA.
The Kernel parameters are now the same as the factory default even though changes were made to best match available resources after a Memory / DIMM upgrade.
This may lead to error messages stating that resources may not be sufficient or are incorrect to startup database, processes or applications.

Changes

1. ODA physical memory upgrade on the ODA beyond the base size ( e.g. 256g)
2. OS Kernel parameters changed to use the improved memory available
3. Patch bundle / Upgrade applied
4. Kernel parameters previously set for the improved memory resources change back to the old memory values
5. OS warnings that parameters are not set properly or resources can not be started due to OS kernel parameter settings

Cause

Internal Bug 25192165

Solution

1) Manually change the Kernel parameters to your pre-patch application values

2) IF you have increased memory to 512G or 768G per server you can use 768G recommended Kernel parameter

settings for the ODA if using 50+ databases
===============================

The following was the maximum creation on X5-2 fully populated (768G), this has been tested .

1. Increase kernel.sem from ‘250 32000 100 142’ to ‘1510 214420 1510 200’ on both nodes.

# vi /etc/sysctl.conf
kernel.sem=1510 214420 1510 200

# sysctl -p /etc/sysctl.conf

2. Increase the hugepages from 67200 to 103865 on both nodes as below:

# vi /etc/sysctl.conf
vm.nr_hugepages=103865
# sysctl -p /etc/sysctl.conf

3.Increase memlock limit from 192000000 to 256000000 on both nodes as below:

# vi /etc/security/limits.conf
oracle soft memlock 256000000
oracle hard memlock 256000000

Each database has following configurations:

alter system set sga_target=4g scope=spfile sid='*';
alter system set pga_aggregate_target=2g scope=both sid='*';
alter system set processes=1500 scope=spfile sid='*';
alter system set cpu_count=8 scope=both sid='*';

References

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