A Conversation for H2G2 unix users (H2G2U2)

command confusion

Post 1

tiptop

Hello - does anybody ever come here, or have I just walked into a ghost town?

Perhaps if I shout my question really really loud one of you will hear it and may be able to point me in the right direction.

Does anybody know a command which will show me system usage? [Percentage CPU usage? Disk I/O? Available memory (as a percentage)?]

I need to roll some software out to a box and I'd like to do it at a quiet time. How would one know whether or not a box was quietly idling away or charging around at full steam? (BTW, the box mostly runs back-office processes so showing the number of users doesn't mean much)

TIA

tiptop


command confusion

Post 2

TjabaTjenaHallo

well it would be helpful if you provided a clue as to what o/s you
are running. but..... if its unix-like "top" might be helpful
something like, top -b 0 >> somefile run from cron at 10 minute
intervals will do the trick. Many unix systems hace a thing called sa
which will provide detailed info about what is going on.

If its an NT / Win2K box then there are performance monitor tools
which can log the same kind of info to a file for later analysis
curiously enough, this is one of the very few places where NT
built in tools are better then Unix.

If its a MAC...I have no idea

If its anything else...


command confusion

Post 3

Peter Gathercole

Many Unixes have the commands vmstat and iostat which will tell you information about the memory and disk usage of the system. They also both tell you about CPU usage. Both of these take arguments of the interval between the samples, and the number of samples that you want.

Sa, which is usually called sar (sa is the data collector) is a historic tool that has been with Unix for as long as I can remember. Nowerdays, most commercial Unixes have not has sar updated for the most recent changes (like multi-processor support), and it is likely that if you get sar working, it may provide misleading (although probably not wrong) information. There used to be an addon to sar called sag, which would plot the collected data on a Tektronix storage terminal (or emulation) but this appears to have disappeared on many systems. I still miss this tool, as it gave a good first cut of the performance of the system, without investing in one of the commercial addons. And it was very useable.


command confusion

Post 4

Spelugx the Beige, Wizard, Perl, Thaumatologically Challenged

What about just using w or uptime to look at the load average (type cat /proc/loadavg under Linux). That should give a good indication of heavily loaded the system is.


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