[GRLUG] Solid State Drives

[Adam Tauno Williams]

> > There really is no danger in leaving cruft in RAM so long as there is 
> > still free RAM. It is only when the RAM has been nearly exhausted that 
> > things need to be removed. It's a balancing act because it takes a long 
> > time to save things to swap and a long time to get them back (compared 
> > to RAM speed.) A tiny bit of swap usage (say, upwards of 10-15% of your 
> > RAM size or 250MB whichever is smaller) can help things out. Past that 
> > it's an albatross around your neck and you just need more RAM.
> 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.  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). 

> 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.

> again, it seems like I completely over did it with a 2GB swap.  Is there
> any benefit to reducing it (other than freeing up some disk space, which
> is not an issue)?

No.