What happens if i lower the number for "Sessions Lifetime" from 120 min to about 10 min, will this affect the seed of my site via database error etc?
It means that once a user leaves your website (closes the TAB or window) if the user opens your website again after 11 minutes the user will need to login. This is also valid if no action is done for 11 minutes (when uploading though i'm using ajax to keep the session open). Decreasing the session lifetime wont improve performance. Also using the database for saving session data wont improve performance. Using memcached to save the session data will improve performance. Also using ssd or in memory partition for the session path partition will improve performance.