Highwater mark for swap

[Terence O'Donovan]

We have various processes that go out into our universe of servers and report back storage usage and so on - including swap space. These
processes are started in off-peak time and so, obviously, there is very little swap activity going on.

Does anyone know of a way to get some sort of highwater mark for swap usage during the day (or since the last time we checked)? It would be perfect if it could report the highwater mark by device.

Thanks in anticipation.

Regards,

T.

p.s. Prefer not to install any new software as we're talking about over 1,200 hosts

[Patrick Wallek]

If you've got MeasureWare installed on your machines, then you can use its statistics. If I recall correctly one of the things it keeps track of is swap usage.

Have a look at the 'extract' command to find out how to extract information from MeasureWare's log files. 'man extract' if you have MeasureWare.

If you don't have MeasureWare, I think you may be out of luck.

[Bill Hassell]

There is no metric kept in the OS for a highwater mark. Swap usage simply goes up and down just like filesystem usage. You would have to run swapinfo into a file via cron and then analyze the results on a regular basis. Or use Measureware which wil provide MUCH more in terms of stats. You'll find that Measureware is invaluable for measuring server performance.

[A. Clay Stephenson]

Measureware is by far the better choice but a poor man's method would be to run sadc (sar data collector) at perhaps 20 minute intervals during the day, and then let your nitely processes run sar -w on the sadc file. There is really no option to display swap usage by disk and really no need for one.