Friday, August 9, 2013

Post 55 of series - Install Oracle RAC 12c on Vmware with Windows 7 64-bit as host OS and Linux CentOS or RHEL 6 as guest OS (Part 8, Fix shared memory problem before container database install)


The true society is the company of those who meditate on the Name of the Lord. Do not associate with those, O Nanak, who look out only for their own interests. || 2 || PAUREE: Approved is that time, when one meets the True Guru. Joining the Saadh Sangat, the Company of the Holy, he does not suffer pain again. When he attains the eternal place, he does not have to enter the womb again. He comes to see the One God everywhere. He focuses his meditation on the essence of spiritual wisdom, and withdraws his attention from other sights. All chants are chanted by one who chants them with his mouth. Realizing the Hukam of the Lord's Command, he becomes happy, and he is filled with peace and tranquility. Those who are assayed, and placed in the Lord?s treasury, are not declared counterfeit again.





Problem:

On my other VM I had the following problem after I installed the container databases on top of the database
we created in the last post. So lets fix this before installing container database:

WARNING: You are trying to use the MEMORY_TARGET feature. This feature requires the /dev/shm file system to be mounted for at
least 754974720 bytes. /dev/shm is either not mounted or is mounted with available space less than this size. Please fix this so                                                                                          
that MEMORY_TARGET can work as expected. Current available is 316739584 and used is 663584768 bytes. Ensure that the
mount point is /dev/shm for this directory.



As of now we have following, but we need to to have 4gb pace on mount point /dev/shm :

oracle : rac20.rac.meditate.com : @prabgun1 : /home/oracle
$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_bbm-lv_root
                       84G   20G   60G  25% /
tmpfs                 747M  134M  613M  18% /dev/shm
/dev/sda1             485M   59M  401M  13% /boot
/dev/mapper/vg_bbm-lv_home
                      9.9G  151M  9.2G   2% /home

oracle : rac20.rac.meditate.com : @prabgun1 : /home/oracle
$

Fix:

Configuring Shared Memory
The shared memory can be configured using a swap partition or swap file. Best practice is to create an appropriately
sized swap partition. However, if the existing swap partition exists and is too small, you can add a swap file by following
the example below (as root user):

So, lets fix it by adding space to it.

oracle : rac20.rac.meditate.com : @prabgun1 : /home/oracle
$ df -h /dev/shm/
Filesystem            Size  Used Avail Use% Mounted on
tmpfs                 747M  134M  613M  18% /dev/shm

oracle : rac20.rac.meditate.com : @prabgun1 : /home/oracle
$


Create a 4G swap file, so as root execute the following command on both nodes, node rac20 and rac21
dd if=/dev/zero of=/swap_file_to_increase_shared_mem bs=1M count=4096


Here is the output:

oracle : rac20.rac.meditate.com : @prabgun1 : /home/oracle
$ su - root
Password:
[root@rac20 ~]# dd if=/dev/zero of=/swap_file_to_increase_shared_mem bs=1M count=4096
4096+0 records in
4096+0 records out
4294967296 bytes (4.3 GB) copied, 9.74795 s, 441 MB/s
[root@rac20 ~]#


and

oracle : rac21.rac.meditate.com : @crs : /home/oracle
$ su - root
Password:
[root@rac21 ~]#  dd if=/dev/zero of=/swap_file_to_increase_shared_mem bs=1M count=4096
4096+0 records in
4096+0 records out
4294967296 bytes (4.3 GB) copied, 9.95022 s, 432 MB/s
[root@rac21 ~]#


Setup the
swap file with the command on both the nodes as root:
mkswap /swap_file_to_increase_shared_mem

Here is the output:
[root@rac20 ~]# mkswap /swap_file_to_increase_shared_mem
mkswap: /swap_file_to_increase_shared_mem: warning: don't erase bootbits sectors
        on whole disk. Use -f to force.
Setting up swapspace version 1, size = 4194300 KiB
no label, UUID=fff56d7b-2ed3-4ed7-b909-86f965fd3538
[root@rac20 ~]#


and

[root@rac21 ~]# mkswap /swap_file_to_increase_shared_mem
mkswap: /swap_file_to_increase_shared_mem: warning: don't erase bootbits sectors
        on whole disk. Use -f to force.
Setting up swapspace version 1, size = 4194300 KiB
no label, UUID=57b6e171-1d59-4fff-b474-7433201281e8
[root@rac21 ~]#


To enable it at boot time, edit /etc/fstab to include:
/swap_file_to_increase_shared_mem   swap  swap  defaults    0 0

Though you can use the following to enable the swap file immediately but not automatically at boot time but I am using the
above option as we need to fix the machines permanently:
swapon /swap_file_to_increase_shared_mem


Edit /etc/fstab to set shmfs size at bootup:
shmfs       /dev/shm    tmpfs size=4g    0

If you want to set it on the fly the following but I am not using it and will use the command mentioned above:
mount -t tmpfs shmfs -o size=4g /dev/shm

So now on both the nodes /etc/fstab looks like the following:

[root@rac20 ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Mon Jul 15 00:03:49 2013
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg_bbm-lv_root /                       ext4    defaults        1 1
UUID=a84ca6e5-0680-45b8-96af-150faecab250 /boot                   ext4    defaults        1 2
/dev/mapper/vg_bbm-lv_home /home                   ext4    defaults        1 2
/dev/mapper/vg_bbm-lv_swap swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/swap_file_to_increase_shared_mem   swap  swap  defaults    0 0
shmfs       /dev/shm    tmpfs size=4g    0

[root@rac20 ~]#


and

[root@rac21 ~]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Mon Jul 15 00:03:49 2013
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/vg_bbm-lv_root /                       ext4    defaults        1 1
UUID=a84ca6e5-0680-45b8-96af-150faecab250 /boot                   ext4    defaults        1 2
/dev/mapper/vg_bbm-lv_home /home                   ext4    defaults        1 2
/dev/mapper/vg_bbm-lv_swap swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/swap_file_to_increase_shared_mem   swap  swap  defaults    0 0
shmfs       /dev/shm    tmpfs size=4g    0

[root@rac21 ~]#

Now reboot both the machines and you should see the following "df -h" output:

oracle : rac20.rac.meditate.com : @crs : /home/oracle
$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_bbm-lv_root
                       84G   24G   56G  30% /
tmpfs                 4.0G     0  4.0G   0% /dev/shm
/dev/sda1             485M   59M  401M  13% /boot
/dev/mapper/vg_bbm-lv_home
                      9.9G  151M  9.2G   2% /home
shmfs                 4.0G     0  4.0G   0% /dev/shm

oracle : rac20.rac.meditate.com : @crs : /home/oracle
$


and

oracle : rac21.rac.meditate.com : @crs : /home/oracle
$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_bbm-lv_root
                       84G   19G   61G  24% /
tmpfs                 4.0G     0  4.0G   0% /dev/shm
/dev/sda1             485M   59M  401M  13% /boot
/dev/mapper/vg_bbm-lv_home
                      9.9G  151M  9.2G   2% /home
shmfs                 4.0G     0  4.0G   0% /dev/shm

oracle : rac21.rac.meditate.com : @crs : /home/oracle
$


The True Guru is the boat; the Word of the Shabad will carry them across. There is neither wind nor fire, neither water nor form there. The True Name of the True Lord is there; it carries them across the terrifying world-ocean. || 2 || The Gurmukhs reach the shore beyond, lovingly focusing on the True Lord. Their comings and goings are ended, and their light merges into the Light. Following the Guru?s Teachings, intuitive peace wells up within them, and they remain merged in the True Lord. || 3 || The snake may be locked in a basket, but it is still poisonous, and the anger within its mind remains. One obtains what is preordained; why does he blame others? If one, as Gurmukh, hears and believes in the Name, the charm against poison, his mind becomes content. || 4 || The crocodile is caught by the hook and line; caught in the trap of evil-mindedness, he regrets and repents, again and again. He does not understand birth and death; the inscription of one's past actions cannot be erased. || 5 || Injecting the poison of egotism, the world was created; with the Shabad enshrined within, the poison is eliminated. Old age cannot torment one who remains lovingly absorbed in the True Lord. He alone is called Jivan-Mikta, liberated while yet alive, from within whom egotism is eradicated.


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