[buug] Using swap on an SSD...or not.

Rick Moen rick at linuxmafia.com
Tue Sep 29 15:19:08 PDT 2009

Quoting Zeke Krahlin (pewterbot9 at gmail.com):

> Well, I stated my RAM to be 500M...and that may be fine for my
> stand-alone, single-user system.

That would depend entirely on what you choose to run on it.  My old
iBook 2.2 PowerPC laptop has only 256 MB RAM, and runs Debian
without hitting swap, running my usual mix of xterms and a Web
browser.[1]  (Actually, it's OK in that department even with Xubuntu.)

But Your Mileage May Differ<tm>.  Suggest you get to be buddies with ps,
top, vmstat, etc., to see how much RAM you really use.

> Tomorrow, I'll run my little Eee PC 701SD w/Firefox and a few other
> programs while wifi connected...and see just how much memory is used.

No offence intended, but do you know how to do that?

"vmstat 1" will do a report on swap activity every second, until you
Ctrl-C out of it.  The "si" and "so" columns reports data swapped in and
swapped out -- in kilobytes by default, I think.  On _my_ system in
front of me, it registers zeroes all the time, because I'm not hitting

Be aware:  Even a system that's not actually needing swap will touch it
a _little_ from time to time, if it's available and switched on.  You'll
know the difference (watching vmstat) when you add an additional process
and it starts hitting swap for real.

[1] I like my process table (ps auxw | more) to be clean and not chewing up
RAM and other system resources running junk that _I_ didn't decide to
run, which is why I tend to eschew "desktop environment" suites that
spawn off a forest of obscure processes, and instead run a simple
minimalist window manager.

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