During a backup triggered via the management console, IWSVA uses the migration.sh script under /usr/iwss to back up the configuration database policies to a compressed tar archive: /var/iwss/migration/export/IWSVA5.0_Config.tar.

To use a CRON job, it will have to run from the /usr/bin directory.

• bash-3.2# crontab -e
  crontab: installing new crontab
• bash-3.2# crontab -l
  0-59/2 * * * * /usr/iwss/bin/systemupdate > /dev/null 2>&1
  */5 * * * * /usr/iwss/bin/svc_snmpmonitor_root.sh > /dev/null 2>&1
  30 * * * * /usr/iwss/migration/migration.sh
• bash-3.2# crontab -e
  crontab: installing new crontab

Reference: Crontab – Quick Reference