Originally posted by: RafitaTecnocom

Hi guys,

I installed Oracle 12c with 8 databases. The memory associated to this databases are the following:

So, not more than 12GB used.

The serves has 26 GB of memory but only less than 100 MB free, so when there are many connections to the listeners, the listener try to get memory and cannot , so it freeze.

I do not know the process who is killing me the server memory. 

At the begining was problem of FS Cache but I limited by setting :

ioo -p -o j2_inodeCacheSize=40 
ioo -p -o j2_metadataCacheSize=40 

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The detail about memory are the following:

 

** overall **
Free Mem: 93.0625 MB out of Total Memory: 26624 MB

** Applications Programs **
Shared Segments 9314.68 MB
Shared Code binaries 821.954 MB
Private Mem 11919.5 MB

** System : Kernel + FS Cache **
Kernel = 3515 MB
Cache FS: 970.332 MB

** overall again **
Free Mem: 91.9023 MB out of Total Memory: 26624 MB

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BTW, I thing listeners are consuming a lot of memory. Isn't it?

 svmon -P -O summary=basic,unit=MB | grep lsn
28967074 tnslsnr         413.59     39.5     4.94   516.23
29556924 tnslsnr         412.56     39.5     4.94   515.22
16842772 tnslsnr         412.12     39.5     4.94   514.79
29425838 tnslsnr         412.12     39.5     4.94   514.77
25166000 tnslsnr         411.77     39.5     4.94   514.41
29294764 tnslsnr         411.57     39.5     4.94   514.22
20185092 tnslsnr         411.57     39.5     4.94   514.22
29098148 tnslsnr         411.50     39.5     4.94   514.15

 

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I read many things about minperm and maxperm but I did many changes and nothing.

Could someone help me with this issue?

Useful parameters:

             ame_cpus_per_pool = n/a
               ame_maxfree_mem = n/a
           ame_min_ucpool_size = n/a
               ame_minfree_mem = n/a
               ams_loan_policy = n/a
  enhanced_affinity_affin_time = 1
enhanced_affinity_vmpool_limit = 10
                esid_allocator = 1
           force_relalias_lite = 0
             kernel_heap_psize = 65536
                  lgpg_regions = 0
                     lgpg_size = 0
               low_ps_handling = 1
                       maxfree = 1088
                       maxperm = 5231014
                        maxpin = 6161044
                       maxpin% = 90
                 memory_frames = 6815744
                 memplace_data = 0
          memplace_mapped_file = 0
        memplace_shm_anonymous = 0
            memplace_shm_named = 0
                memplace_stack = 0
                 memplace_text = 0
        memplace_unmapped_file = 0
                       minfree = 960
                       minperm = 326938
                      minperm% = 5
                   msem_nlocks = 0
                     nokilluid = 0
                       npskill = 25344
                       npswarn = 101376
           num_locks_per_semid = 1
                     numpsblks = 3244032
               pinnable_frames = 5342627
           relalias_percentage = 0
                         scrub = 0
                 thrpgio_inval = 1024
                thrpgio_npages = 1024
                      v_pinshm = 1
                  vm_mmap_bmap = 1
              vmm_default_pspa = 0
                vmm_klock_mode = 2
            wlm_memlimit_nonpg = 1

 

 

Thanks in advance for your help.

All the best.

 

#AIX-Forum

Originally posted by: AncientAIXer

AIX is slowly moving toward Linux in compatibility and philosophy.  A Linux "guru" one time told me that "free memory is wasted memory".  In that vein, Linux and now AIX has moved to only providing a miniscule amount of allowed "free" memory.  The rest is made up of memory used and cached memory.  To determine actual memory consumption, run a performance tool such as "svmon -G".  Divide the virtual memory by the memory size.  This will be the percent of memory actually being used.  Ref: http://www.aixhealthcheck.com/blog?id=255

Earlier in my experience with Linux on my laptop, it was very slow.  I found out of 4 Gb of memory, my Linux distro allocated only 12 Mb of allowed free memory.  Now some may feel this is enough, but I don't.  The problem is that when you decide to run a program that could be 10's if not 100's of Mb in size, the kernel must then decide which of the cached memory must be thrown away to load the program.  I decided out of 4 Gb, a reasonable amount to leave free for programs to load is at least 125 Mb.  I set the allowed free memory to that size and my speed increased dramatically.

With that being said, here is what is happening on your server.  The first thing I noticed was that the minfree is 960 and maxfree is 1088.  This is in pages, so it is3.9 and 4.5 Mb, respectively.  The memory has to drop below minfree before the page cleaners kick in.  They stop when maxfree is reached.  Depending upon the whether your databases are designed for OLAP or OLTP processing, they will require a certain amount of cached memory for repeated queries.  Several references that could help are: https://www-304.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.performance/real_memory_mngment.htm  and https://www-304.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.performance/vmm_page_replace_tuning.htm

Both IBM and Oracle have published many papers on performance tuning.  Google "AIX Oracle tuning" to find them.  Some of the papers for older versions of Oracle are usually still relevant with newer versions.

Good Luck

#AIX-Forum