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

[Rick Moen]

Quoting Zeke Krahlin (pewterbot9 at gmail.com):
 
> What *prompted* me to ask about using swap on an external SDHC card,
> was that I read that solid state drives have a limited write capacity
> considerably lower than your standard hard drives...significant enough
> to be worth the trouble of moving swap off the SSD. Has nothing to do
> with excessive swap problems.

I understood all that, and used the phrase "excessive swap" to (in my
view) encompass _any_ swap activity on NAND flash devices.  (Both your
netbook's SSD and any SDHC cards are based on NAND flash chips.)

> --Here is my report:
> 
> Well, "sdc5" is the device label for my SDHC card's swap partition, so
> the line would read:
> 
>    /dev/sdc5       none            swap    sw              0       0
> 
> But it doesn't. Here's my fstab's present swap line:
> 
>    # swap was on /dev/sda5 during installation
>    UUID=d58c09be-5890-4cd3-93ba-67bb6f01bf3f none            swap    sw
> 
> Obviously, Ubuntu uses "universally unique identifier", so I found
> this help page:

Yes, you can fix that, if you wish, by replacing the unspeakable
UUID=foo strings with /dev/* nodenames.  I would.


> System Monitor 

I would not use or trust "System Monitor".  If you wish to convey
reliable information to other members of the *ix community, you should 
copy and paste from standard tools, e.g., ps, "cat /proc/meminfo", 
vmstat, and so on.

> What do I have running on my Eee PC 701SD at this moment?

I would not use or trust "System Monitor".  If you wish to convey
reliable information to other members of the *ix community, you should
copy and paste from standard tools, e.g., ps, "cat /proc/meminfo",
vmstat, and so on.

> However, Nautilus uses 10.5MB of RAM according to the processes
> list.

It is doubtful that you have any competent and reliable information
about the process list.  See foregoing.

Yes, ps and top are a bit peculiar and user-hostile, and the meaning of
VIRT, RES, SHR in top, and RSS, VSZ in ps are initially challenging.
It's worthwhile persevering, because it's real and meaningful.


> Time to reboot, and see how that 10 swappiness goes!  :\

Should work.  However, if you're going to be tweaking things like
swappiness, I might suggest keeping a written log on paper of a all
siginficant changes you make to your system, so you can backtrack
if something goes sideways.  Composition books and legal pads are
suitable, in my experience.