Activate memory in Linux at run time using bash - vmware

In following with my previous post about "Adding scsi device at runtime on linux guest VM," I am adding some information here on how to use a bash "for-loop" to activate memory; it was added at runtime on a VMWare guest.

I've tested this on a CentOS 5.5 system.

First, add the new memory using VMWare VSphere.

Second, find the new memory that is currently listed as "offline".

[root@... ~]# grep offline /sys/devices/system/memory/*/state
/sys/devices/system/memory/memory40/state:offline
/sys/devices/system/memory/memory41/state:offline
/sys/devices/system/memory/memory42/state:offline
/sys/devices/system/memory/memory43/state:offline
/sys/devices/system/memory/memory44/state:offline
/sys/devices/system/memory/memory45/state:offline
/sys/devices/system/memory/memory46/state:offline
/sys/devices/system/memory/memory47/state:offline
/sys/devices/system/memory/memory48/state:offline
/sys/devices/system/memory/memory49/state:offline
/sys/devices/system/memory/memory50/state:offline
/sys/devices/system/memory/memory51/state:offline
/sys/devices/system/memory/memory52/state:offline
/sys/devices/system/memory/memory53/state:offline
/sys/devices/system/memory/memory54/state:offline
/sys/devices/system/memory/memory55/state:offline
/sys/devices/system/memory/memory56/state:offline
/sys/devices/system/memory/memory57/state:offline
/sys/devices/system/memory/memory58/state:offline
/sys/devices/system/memory/memory59/state:offline
/sys/devices/system/memory/memory60/state:offline
/sys/devices/system/memory/memory61/state:offline
/sys/devices/system/memory/memory62/state:offline
/sys/devices/system/memory/memory63/state:offline
/sys/devices/system/memory/memory64/state:offline
/sys/devices/system/memory/memory65/state:offline
/sys/devices/system/memory/memory66/state:offline
/sys/devices/system/memory/memory67/state:offline
/sys/devices/system/memory/memory68/state:offline
/sys/devices/system/memory/memory69/state:offline
/sys/devices/system/memory/memory70/state:offline
/sys/devices/system/memory/memory71/state:offline


Then, use a for loop to activate that memory:

[root@... ~]# for memcount in {40..71}; do echo online > /sys/devices/system/memory/memory$memcount/state; done


Check the new memory is active:

[root@... ~]# free -m
             total       used       free     shared    buffers     cached
Mem:          8045        854       7190          0          8         87

Add date to Bash History

In order to add a date stamp to your bash history add the following two lines to your .bash_profile:

HISTTIMEFORMAT='%F %T '

export HISTTIMEFORMAT

Alternativelly, you can set this variable globally and have all history files keep the data by setting these two lines in a file under the /etc/profile.d directory.

echo "HISTTIMEFORMAT='%F %T '" > /etc/profile.d/histtimestamps.sh

# echo "export HISTTIMEFORMAT" >> /etc/profile.d/histtimestamps.sh

# chmod +x /etc/profile.d/histtimestamps.sh

Your history will look like this:

...

902 2012-02-16 09:50:33 cd /var/log

903 2012-02-16 09:50:33 ll

904 2012-02-16 09:50:33 ls -lat | sort -t

905 2012-02-16 09:50:33 ls -lat

...