tmpfs /dev/shm

bgeary · 05-06-2010, 05:19 PM

Hello:

I was not able to find these answers via a search on google.

1) In our tmpfs /dev/shm we have what seem to be unused/stale files. Can these be safely deleted by using 'rm'.

2) How is the space calculated for tmpfs /dev/shm?
So for instance if we have unused/stale files are these in the calculation of space used?

Red Hat Enterprise Linux Server release 5.4 x86_64

Fs Size Used Avail Use% Mounted on
tmpfs 32G 25G 7.9G 76% /dev/shm

Thank You
bg

stuart_cherrington · 05-10-2010, 11:36 AM

According to Redhat doc's /dev/shm is 1/2 the physical memory assigned to the server. So, from your 'df' output you should have 64Gb memory in use. /dev/shm is used to store 'Shared Memory' pages for applications running on the server, but it stores the pages in memory so its faster to access. So, no, I wouldn't delete files from here, you could use 'lsof' to check on file/page usage but deleting them seems a little extreme. If you can reboot, then this would safely clean /dev/shm.

HTH

Stuart.

bgeary · 05-10-2010, 11:51 AM

Quote:

Originally Posted by stuart_cherrington

According to Redhat doc's /dev/shm is 1/2 the physical memory assigned to the server. So, from your 'df' output you should have 64Gb memory in use. /dev/shm is used to store 'Shared Memory' pages for applications running on the server, but it stores the pages in memory so its faster to access. So, no, I wouldn't delete files from here, you could use 'lsof' to check on file/page usage but deleting them seems a little extreme. If you can reboot, then this would safely clean /dev/shm.

HTH

Stuart.

Stuart:

Thanks. The issue we are having is that Oracle says it does not have enough memory to start. We were trying to determine if this is because of stale/leftover files in /dev/shm that were being counted as part of the free/available stats. We only started having this problem recently and this is when we noticed these leftover files. So this is why we are trying to determine if we can delete or even if RH is counting these in the free/availalble memory stats.

Thanks again
bg

DrLove73 · 05-11-2010, 04:33 PM

Red Hat support should be more then competent to provide you with answers since you are paying them to be there when you need them the most.

bgeary · 05-12-2010, 07:56 AM

Quote:

Originally Posted by DrLove73

Red Hat support should be more then competent to provide you with answers since you are paying them to be there when you need them the most.

Thanks. I am trying to get my account setup with them but it is taking a bit long. So yes I will be contacting them.

Thanks