[GRLUG] Solid State Drives

[John-Thomas Richards]

On Mon, Dec 01, 2008 at 10:53:44AM -0500, Adam Tauno Williams wrote:
[snip]
> > I have two GB RAM on my laptop and almost never access swap.  Currently,
> > with Firefox running along with several xterms, a couple other gui apps
> > and a bunch of e17 modules loaded, I have 667,888k of RAM free with 0k
> > of swap used.  The only time I ever see the swap partition used is when
> > basketbawful (the *best* NBA blog there is) has, like, 20 youtube videos
> > in one post.  
>
>  I have a server with 8Gb of RAM and 8Gb of SWAP and an average of
> something like 60% swap used - the performance is great.  I've got 4Gb
> in my laptop and usually have ~100MB in the swap (sometimes it surges
> upward) - performance is good.  I don't think measuring utilization of
> swap is a meaningful performance benchmark at all;  paging is what is
> bad.

I agree that paging is the real issue (being so much slower).  I was
simply pointing out that my system almost never swaps out *anything*.  I
almost always have Firefox, liferea, kile, several xterms, etc. running
and it seems odd to me that with *only* 2GB RAM, I almost never need
swap.  I think that is a meaningful measure of performance.  I don't
have the chops to really discuss memory management, but it seems to be
that if I almost never need swap, my system is performing well.  That
may simply be the types of applications I use and the fact that I rarely
compile anything (well, except for keeping e17 up-to-minute :-).  It may
also be that e17 has very low memory requirements.  Whatever the reason
I almost never need swap.

> To know your paging rate you need to watch something like dstat;
> a tiny bit of swap with allot of paging is bad,   a large amount of used
> swap with essentially no paging is just fine (possibly even good). 

dstat is new to me.  Thanks.  I installed it; it looks really
useful.

> > Sometimes I wonder why I have a swap partition.  Then
> 
> Swap is a good safety net, it lets the OS get out of a corner if things
> go badly.  I have 6GB of swap on my laptop, and 4GB on my workstation.
> Given disk capacity it is an essentially free release valve.

Why do you have so much more on your laptop than your workstation?

[snip]
-- 
john-thomas
------
There is no opinion so absurd that some philosopher will not express it.
Marcus Tullius Cicero, "Ad familiares"