If you are using Dedicated server or Virtual private server, files or directories access,modify,changes,logs reports time based on 
your timezone settings. First know your current system time command is "date".

Current Date :

​# date
Wed Feb 26 02:26:19 IST 2015


Timezone series files are located at /usr/share/zoneinfo, choose appropriate  timezone location as you like, 

Change TimeZone :

Do you want to chnage timezone setting you have root access permission steps are,

Option 1:

Remove the localtime under /etc/ directory and give softlinks,

The below commands will set timezone to Asia/Calcutta.
 
# rm -f /etc/localtime

# ln -s /usr/share/zoneinfo/Asia/Calcutta /etc/localtime

Option 2:

Another method is,
 
# export TZ=Asia/Calcutta

# date

Now, ensure your timezone format configured correct time,
 
# cd /usr/share/zoneinfo

# find * -type f -exec sh -c "diff -q /etc/localtime '{}' > /dev/null && echo {}" \;


Asia/Calcutta

Asia/Kolkata

posix/Asia/Calcutta

posix/Asia/Kolkata


To show numeric timezone format,
 
# date +'%:z %Z'


+05:30 IST