On reboot the server time can be out of sync, because hard clock is out of sync. This can be checked by running”hwclock; date” and comparing the results. In Red Hat 6, the ntpdate start-up script is is separate from…
Linux administration, Linux/Unix Tips and Tricks, RedHat, Unix Shell Scripting, Unix/Linux Performance
How to get CORRECT memory usage for Linux
One of the most common mistakes made by Linux users, is to run free (Mem: line) or sar to get memory utilization. The memory used fields include the space used by the OS to cache files and directory info cace,…
Monitoring Oracle Active Session History (ASH)
To monitor Oracle Active Session History (ASH) run the following query: select total_size,awr_flush_emergency_count from v$ash_info;