Solaris 10 and Oracle 10g - swap space problem

  • From: "Crisler, Jon" <Jon.Crisler@xxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 28 Jul 2009 19:31:16 -0400

On Solaris 10, when I start my databases, I see my swap space usage
increase in a one for one ratio with memory utilization.   System has
64gb of memory.  If I start up a 4gb database, I see 4gb of real memory
used and 4gb of swap space used up as well (as shown by top, swap -l,
swap -s etc.).     This is purely a Oracle database server, and
/etc/system and projects / resource controls seem to be set up, so I do
not understand why swap is being touched.  If I stop all oracle
processes, swap drops down to about 100 Mb used.

 

I have taken great pains to make sure that NO swap is being used, yet
any little allocation of Oracle gets tossed into swap.  I don't know
where to look after this- I would have suspected /etc/system or resource
control / projects to be at fault, or /etc/security (ulimits) but
everything looks ok.    The system has 64g real, and about 54 gb swap-
if I get close to 54gb memory allocated oracle will return out of memory
errors..  Needless to say the system crawls.

 

What am I overlooking ?  TOP and swap -s / swap -l agree so its not a
TOP anomaly 

 

Example from TOP - I have 20g free, so why so much used in swap ?

 

load averages:  0.64,  0.57,  0.46
00:26:34

1073 processes:1071 sleeping, 2 on cpu 

CPU states: 98.3% idle,  1.2% user,  0.5% kernel,  0.0% iowait,  0.0%
swap

Memory: 64G real, 20G free, 40G swap in use, 17G swap free

 

   PID USERNAME LWP PRI NICE  SIZE   RES STATE    TIME    CPU COMMAND

  1997 oracle     1  39    0 4376K 2592K cpu/50   0:02  0.04% top 

  3454 oracle     1  52    0   16G   16G cpu/32   0:00  0.03% oracle

  3456 oracle     1  24    0   16G   16G sleep    0:00  0.03% oracle 

 18589 oracle     1  59    0   16G   16G sleep    0:13  0.02% oracle

 

Swap -s  

total: 39170184k bytes allocated + 2262264k reserved = 41432448k used,
18017608k available

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