Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17


Consultation for changing the parameter MEMORY_TARGET

Posted on 2015-01-12
Medium Priority
Last Modified: 2015-01-12
Hi experts,
In a RAC ASM 11g, Linux  (RedHat  2.6.18), with 2 instance, I need to modify:
memory_max_target parameters (static parameter) 
memory_target (dynamic).

Open in new window

Both in 8G ( currently have 6G)
I received a recommendation that tells me tweak in /etc/fstab:
 /dev/shm ----> defaults, size = 8G,

Open in new window

and then:
mount -o remount / dev / shm

Open in new window

In addition to the statements:

Open in new window

then, in both nodes:
shutdown immediate

Open in new window

Currently the line in fstab says:
tmpfs /dev/shm tmpfs defaults, nosuid, nodev 0 0

Open in new window

Is it necessary to make this change in the fstab?
Would appreciate a look from you and the basic steps to perform the task.
Thank you very much
Question by:carlino70
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
LVL 74

Expert Comment

ID: 40545068
yes, you need to make your tmpfs large enough to hold your MEMORY_MAX_TARGET.

You are trying to hold 7.6G of oracle memory inside 6G of allocation.

my guess is you are seeing ORA-00845 errors because of this.

So, make /dev/shm larger or your memory_max_target lower

Author Comment

ID: 40545136
I'm not seeing errors like ORA-00845 in AlertLog
But if the base, shows slow queries and runs Oracle jobs.

Author Comment

ID: 40545142
sorry, I wrote bad:
But the database, shows slow queries and runs Oracle jobs.
Prepare for your VMware VCP6-DCV exam.

Josh Coen and Jason Langer have prepared the latest edition of VCP study guide. Both authors have been working in the IT field for more than a decade, and both hold VMware certifications. This 163-page guide covers all 10 of the exam blueprint sections.

LVL 74

Accepted Solution

sdstuber earned 2000 total points
ID: 40545149
The instance shouldn't start if you have memory_target (or max_memory_target) of 7.6G with only 6G of shared memory.

Maybe I misunderstood what you posted above, are all of those code boxes suggestions or are some of them what you currently have?

I thought the 8G change was the suggestion and the rest was what you actually had, in which case I would expect an error.

If all of it is a suggestion, then yes, go with that.  It should work.

Author Closing Comment

ID: 40545166
Excellent!, Thanks
LVL 74

Expert Comment

ID: 40545168
Glad I could help.

Making sure your shared memory at the OS level is big enough for the instance's memory is just an extension of the same thing you would have had to do when the database was created.

Configuring /dev/shm to be big enough is one of the preinstallation requirements

Here you're already installed, but if you're making your instance bigger, then same idea as the preinstall.  You must also make the /dev/shm big enough to hold it.

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article started out as an Experts-Exchange question, which then grew into a quick tip to go along with an IOUG presentation for the Collaborate confernce and then later grew again into a full blown article with expanded functionality and legacy…
How to Unravel a Tricky Query Introduction If you browse through the Oracle zones or any of the other database-related zones you'll come across some complicated solutions and sometimes you'll just have to wonder how anyone came up with them.  …
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
This video shows how to Export data from an Oracle database using the Original Export Utility.  The corresponding Import utility, which works the same way is referenced, but not demonstrated.

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question