Re: Oracle vs OS Memory Utilization

ROAL <ralbertson_at_comcast.net> wrote in news:4cd15746-7510-41d6-8368- 20c98938640c_at_r66g2000hsg.googlegroups.com:

> I have a Solaris server V445 running:
> 5.10 Generic_120011-14 sun4u sparc SUNW,Sun-Fire-V445
>
> The server has 8G of memory. However TOP only is showing 700M
> available.
>
> The DB instance is only taking up approx 1G in shared memory segment,
> i.e. SGA
>
> GROUP CREATOR CGROUP NATTCH SEGSZ CPID LPID ATIME
> DTIME CTIME
> Shared Memory:
> m 1 0x76125b4 --rw-r----- oracle dba oracle
> dba 36 943734784
>
> BY THE WAY ORACLE 10G:
>
> Connected to:
> Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - 64bit
> Production
> With the Partitioning, OLAP and Data Mining options
>
> SQL> select * from v$SGA;
>
> NAME VALUE
> -------------------- ----------
> Fixed Size 2034632
> Variable Size 486544440
> Database Buffers 419430400
> Redo Buffers 35708928
>
> Why is the server only showing 700M free. I actually brought the
> instance down due to perf issues today then viewed memory. When
> instance was down it was showing 7+G of available memory. As soon as I
> started the instance with no connections the memory immediately
> dropped to 800M available.
>
> Also before bringing instance down swap utilization was at 50% of
> available, i.e. 4G out of 8G.
>
> Curent TOP
> Memory: 8192M phys mem, 762M free mem, 8193M total swap, 8193M free
> swap
>
> At least swap is not being used now.
>
> What is eating up all the OS memory?
>
> NOTE: There is another server running 2 9i instances with 8G of mem
> and 3G in share memory for the 2 instances and this server show 3G
> free mem.
>
> Thanks.
>

What you have described is typical *nix behavior. More than likely what has been swapped out are idle processes owned by root. Use the "ps" command to display the RSS column; where RSS=0 is a swapped out process.
sar -W will show actual pagein & pageout activity. If they are only 2 digit (<100) don't worry about swap.

What problem are you really trying to solve. Visit http://www.orafaq.com/forum/i/74940/ & read the STICKY post at the top of the "Performance Tuning" sub-forum. Received on Thu May 08 2008 - 20:26:45 CDT