ORA-00443: background process “PMON” did not start

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Categories:Linux Oracle

On the day before last day, my client told me the resource of EC2 instance had been increased, so I decided to increase memory setting for Oracle instance.

The total memory was 4G, so I changed the memory_target to 2800M, and set the option of system parameter filesystemio_options to 'setall', then rebooted the instance, and got below error at first:

The error message was a little misunderstanding, and in fact the issue was that the size of /dev/shm was not enough. I modified the /etc/fstab to get a bigger /dev/shm, then remounted it and got below result:

OK, then started the instance again, and got the 443 error:

I checked the alert log and did not find any useful information, also got no help from Oracle support webiste(Metalink), so even I though the memory_target was not so big to cause this issue, I still decreased it and do some tests, but all of these failed again and again.

I installed the instance just on the previous day, so I made sure it worked well before the change, and I knew if I roll-backed the change it should work again. But now the memory was increased from 2G to 4G, and I did want to make use of more memory. So something was different now, and I should find it.

I recalled one thing that on RHEL7, the /etc/rc.local would not be called after the fresh installation, and I did add one line in it to enable the swap file. so I checked the memory usage again:

I noticed there was no swap space. Was this the reason? Now the memory size changed, so I made a new swap file and started the instance again:

And I checked the memory usage again:

So even the swap space was not used, if the configured memory_target was large and could not be placed in the memory, the instance would not be started!

But why I made the swap file? Why not use a swap partition directly?

  1. There is no swap for some kinds of AWS EC2 instance.
  2. The default file system is XFS on RHEL7, and it could not be shrunk.

So when you create a XFS file system, you have to plan the size carefully as it cannot be reduced online like EXT4/3.

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