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Multiple instances in same server.

BSalesRashidNov 13 2013 — edited Dec 4 2013

Hi people,

I am using Oracle 10.2.0.1 Standard Edition in all instances, on Redhat 5

I just depared with an environment that have 7 instances in a server. I have never seem something like that. There environments are Development/Homologation.

The thing is, i think that the DBA who did this [not me], configurated the thing wrong:

Cpu(s):  0.2%us,  0.1%sy,  0.0%ni, 99.7%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st

Mem:  65958496k total, 65639792k used,   318704k free,   564780k buffers

Swap: 67993592k total,  1109024k used, 66884568k free, 63224848k cached

[oracle@xxxx ~]$ free -m

             total       used       free     shared    buffers     cached

Mem:         64412      64094        317          0        551      61743

-/+ buffers/cache:       1799      62612

Swap:        66399       1083      65316

As you can see, all the memory is in use, and swap is being used a lot.

I also can say that the Oracle background processes are the greater consumer of memory here:

ps -e -orss=,args= | sort -b -k1,1n [Top memory, desc order)

505124 ora_j000_T1HOM

524204 ora_j000_T1DEV

617044 ora_mmon_DBD

824432 ora_mman_DBHd

875132 ora_smon_DBDd

955024 ora_smon_DBHd

2237476 ora_dbw2_DBDd

2336208 ora_dbw1_DBDd

2351732 ora_dbw2_DBHd

2353792 ora_dbw1_DBHd

2439864 ora_dbw3_DBHd

2454024 ora_dbw0_DBHd

2454088 ora_dbw0_DBDd

2516736 ora_dbw3_DBDd

The tmpfs was mounted with half memory available:

[oracle@xxxx ~]$ df -h

Filesystem            Size  Used Avail Use% Mounted on

tmpfs                  32G     0   32G   0% /dev/shm

cat /etc/sysctl.conf

# Controls the maximum shared segment size, in bytes

kernel.shmmax = 68719476736

Each instance has:

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

sga_max_size                         big integer 4768M

sga_target                           big integer 4768M

I know that isn't recommended by Oracle using multiple instances in a database. I just need to free more memory on this environment, need to stop swapping.

Do i have to alter parameters at sysctl.conf , or resize sga_max_size for each database ?

I would appreciate some help.

Thanks in advance.

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Locked on Jan 1 2014
Added on Nov 13 2013
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