Huge Swap area being used despite having available ram (Solaris 8....
09/11/2018 11:47
Hello.

I am relatively new to Oracle as a DB, but we use Oracle 9i under thefollowing conditions.

A sun e6500 ten processor system is direct connected to a sunfire V240 twoprocessor system with 8 GB RAM.

Here is my problem. The V240 has high IO wait times when large numbers ofprocesses are underway. The swap in use number goes through the roof whenoracle is running and I still have some 60+% of system memory listed asfree. I also cannot seem to increase the total SGA size beyond what itpresently is without crashing oracle My three questions are: 1) why is oracle using so much swap?2) is there a way to tell oracle on solaris not to use swap (or at leastcurb its appetite for it)3) how can I use more of the system ram (and hopefully decrease the use ofswap) I am attaching the sample output from startup and top commands for context.

As I have indicated, I am somewhat new to oracle, so forgive my ingnoranceof what might be obvious to my learned collegues.

Mike Rowland308-255-6694 ====output from top on DB server======= last pid: 27538; load averages: 0.03, 0.05, 0.0406:42:03163 processes: 162 sleeping, 1 on cpuCPU states: 98.8% idle, 0.0% user, 1.1% kernel, 0.1% iowait, 0.0% swapMemory: 8192M real, 5219M free, 3382M swap in use, 1624M swap free PID USERNAME LWP PRI NICE SIZE RES STATE TIME CPU COMMAND 1104 root 6 59 0 4464K 3680K sleep 382:02 0.09% picld 26596 root 1 59 0 2960K 1880K cpu/0 1:22 0.07% top 27376 oracle 1 59 0 3149M 1098M sleep 0:12 0.03% oracle 1791 root 1 59 0 28M 14M sleep 2:56 0.00% Xsun 1208 root 1 59 0 4928K 1944K sleep 1:01 0.00% skipd 27378 oracle 1 59 0 3149M 1097M sleep 0:09 0.00% oracle 1392 root 1 59 0 6216K 3648K sleep 0:08 0.00% nsrexecd 1391 root 1 59 0 6008K 2880K sleep 0:03 0.00% nsrexecd 27366 oracle 1 59 0 3094M 1081M sleep 0:02 0.00% oradism 1327 root 24 59 0 3616K 2920K sleep 0:02 0.00% nscd 1561 root 7 59 0 2672K 2232K sleep 0:02 0.00% mibiisa 1355 root 1 59 0 1056K 672K sleep 0:02 0.00% utmpd 27374 oracle 1 59 0 3150M 1103M sleep 0:01 0.00% oracle 1479 root 3 59 0 2744K 2088K sleep 0:01 0.00% vold 1249 root 1 59 0 2528K 1488K sleep 0:01 0.00% rpcbind===================== The startup of oracle gives the following outputTotal System Global Area 3222770856 bytesFixed Size 734376 bytesVariable Size 2382364672 bytesDatabase Buffers 838860800 bytesredo buffers 811008 bytesdatabase mountedDatabase opened ===============

Source is Usenet: comp.databases.oracle.server
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Answer score: 5
09/11/2018 11:47 - No, virtual memory is not ONLY used after physical memory is used up.

Pages are being faulted to disk based upon the Least Recently Usedalgorithm most O/Ses implemented. The LRU algorithm is a result of theWorking Set mechanism, observed in the 60's of the previous century.

No program will ever use *all* the memory allocated to it,consequently unused memory regions can be faulted to disk.


Source is Usenet: comp.databases.oracle.server
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Answer score: 5
09/11/2018 11:47 - << No, virtual memory is not ONLY used after physical memory is usedup.

Pages are being faulted to disk based upon the Least Recently Usedalgorithm most O/Ses implemented. >> Can you provide a link or documentation for what you are saying? Iwould love to learn about this some more...


Source is Usenet: comp.databases.oracle.server
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09/11/2018 11:47 - Comments inline below Mike Rowland via DBMonster.com <forum@DBMonster.com> wrote innews:00122eef75d94cc3b288a30a576fe4ad@DBMonster.com: HUH?Which system is the database server system?How much RAM does the E6500 have? What is direct connected? What is running on the V240? Which processes doing what on the V240 are doing all the I/O? What makes you conclude that a larger SGA is a solution to anything? 'Cuz it does. Why is this a concern of yours? NO. Let Solaris & Oracle be good neighbors & get out of their way.

Put users on the system the free RAM will get consumed.

How long after starting Oracle?Solaris were these measurements taken?

Source is Usenet: comp.databases.oracle.server
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09/11/2018 11:47 - Going to sun.com and entering solaris swap in the search box brings upgems like http://www.sun.com/sun-on-net/itworld/UIR980701perf.html .

I'm sure there is more on the subject googling usenet groups.

In times past, some unix required swap space to be available in case itneeded to be used. I'm not familiar with sol8 so I don't know if thatis what you are seeing, but it might not be an issue there.

jg

Source is Usenet: comp.databases.oracle.server
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09/11/2018 11:47 - I would tend to agree with Mr. Rowland. I could be wrong, but myunderstanding is that virtual memory (aka SWAP) is used ONLY afterphysical memory (aka RAM) is used up. So I too would be concerned thatSWAP is being used before RAM is totally used up.


Source is Usenet: comp.databases.oracle.server
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