Re: How much Unix?

"Mr. Majestic" wrote:
>
> If your an Oracle DBA, How much Unix should you know? Shell
> programming? etc....

At the most basic level, you should know how to monitor the activity of Oracle from the operating system level. This involves tools such as 'vmstat' (for watching memory activity), 'iostat' (for watching disk activity) and 'netstat' (for watching network activity). If the database is running slowly, sometimes it's not an Oracle tuning matter - no database can run at optimal performance on a machine that's busy with other tasks. For example, querying the system tables might not show contention, because you've separated your indexes, data, system and temp tablespaces, so the only way to find out is to actually monitor the unix counters. One of the most useful tools for monitoring a unix system is called 'top', which displays uptime, load averages, percentages of time spent in kernel mode, user mode, waiting for I/O to complete, and the top 20 or so most busy processes with their statistics. You can just leave it running in a window and keep an eye on it. Another useful tool is 'truss' - you can connect this to a running process, and it will report the system calls as they are executed, which is invaluable if you have a busy process but don't know what it's currently doing. If you get a core dump, 'gdb' will help you diagnose it. For checking how much disk space you have free, use 'df', and for seeing who's logged on to unix, run 'who' or 'w'. These are the first things to learn, as they will help you with other DBA tasks.

The next thing is probably shell scripting. My personal preferences here are bash and ksh, as they are more powerful than the standard sh. This will allow you to automate common tasks. Perl is an alternative. There are also disk management commands which are platform-specific, for example Solaris has 'metatool' and AIX has the volume group commands. Also, you should know about /etc/system on a Sun, about 'smit' on AIX, etc.

Cheers,

g

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