Unexpected errors at backend of drupal

Hi Team

Somehow we are facing issues related to cache at backend and it stopped the website. Website goes down with "Error "The website encountered an unexpected error. Please try again later." message.

Notice: unserialize(): Error at offset 23 of 117 bytes in DrupalDatabaseCache->prepareItem() (line 457 of /apps/customer/drupal.www.hitachi-america.us.ice/public_html/ice/includes/cache.inc).
Warning: Invalid argument supplied for foreach() in system_list() (line 142 of /apps/customer/sitename/public_html/ice/includes/module.inc).
Warning: array_keys() expects parameter 1 to be array, boolean given in system_list() (line 147 of /apps/customer//public_html/ice/includes/module.inc).
Warning: Invalid argument supplied for foreach() in bootstrap_invoke_all() (line 1343 of /apps/customer//public_html/ice/includes/bootstrap.inc).

I researched and found some help on internet to resolve this issue. Below are steps

Temporary FIX :

Steps:
1: Truncate all cache tables from database
2: Run Update.php at website

After these steps you will be able to login at backend and website is working again. but issues related to "Unserialize" still showing on pages of website.

I don't know why these errors are showing again and again on website and what is the root cause behind.

Is drupal core issue or server side issue that affect drupal CMS. Please help me as I am getting these error on my drupal 7 projects.