Sounds like a fair summation to me :-)
On Sat, 18 Aug 2001 10:30, [EMAIL PROTECTED] wrote:
> Okay, I think I've got my head wrapped around the whole swap size issue.
> Let's play the game of I say what I think swap is, and then you either pat
> me on the head or break out the dunce cap. Here goes:
>
> The point of swap is to serve as a safety net for RAM, when you're all out
> of RAM your computer swaps data in and out of the /swap partition to make
> sure only the most active programs are getting the best electronic real
> estate. It's generally a good idea to have twice the swap space as you
> have RAM space, up to about 200 megabytes of swap. (here's the thing I've
> been confused about...) While it's never a bad thing to have too much swap,
> the x2 up to 200 rule serves to make sure you have at least enough swap.
> If you have more swap than you need it's not a bad thing, the only reason
> it would be bad is if you actually needed that 17 gigs of swap. If you
> needed more than 200MB of swap then you should be upgrading your RAM, but
> if you have 512MB of RAM for your glorified word processor and you want
> 1700MB of swap just because you like the cute little green block in
> diskdrake, there's nothing wrong with having all that unused swap. The
> reasons for saying not to have more than 200MB of swap are:
>
> 1. if you need more than 200MB, you ought to go buy more RAM, and
> 2. if you don't need more than 200MB, you are wasting disk space that could
> be going to other partitions
>
> How'd I do? Thanks for putting up with me, the thing I have been hung up
> on was why too much could be bad.
>
> Frequently,
> Isaac
>
> Quoting Sridhar Dhanapalan <[EMAIL PROTECTED]>:
> > If you're using over 200MB of swap, your system would be moving slower
> > than
> > some continents. There is nothing really _wrong_ in having over 200MB of
> >
> > swap, but there would be nothing to gain. If you need over 200MB
> > (assuming
> > you have a decent level of RAM), either you're doing something _very_
> > memory-intensive (e.g. running a busy server) or (more likely) there is
> >
> > something wrong (like a rogue process or a memory leak).
> >
> > In other words, the 200MB swap limit is simply a rule-of-thumb based on
> >
> > practicality. You don't need to follow it to-the-letter, but you most
> > likely
> > won't gain anything by having anything bigger. In fact, since
> > filesystems
> > tend to become slower as thet become larger, your system could even slow
> > down.
> >
> > RAM is relatively cheap nowadays. The best thing you can do to increase
> > your
> > system speed would be to have enough RAM so that you don't need and swap
> > at
> > all.
> >
> > On Fri, 17 Aug 2001 16:47, [EMAIL PROTECTED] wrote:
> > > Good helpful example. I use ten desktops: 2 for monitoring, one for
> > > superuser terminal, one for email, one for instant messaging, 2 for
> > > browsing, one for writing programs, one non-superuser terminal for
> >
> > running
> >
> > > them, and one for home directory. Yes, I realize this is sort of
> > > outrageously spread out but I'm just sort of playing right now to get
> >
> > a
> >
> > > feel for how I'd like to use the desktops and the Linux software.
> >
> > My
> >
> > > question is: since having all these things open only ever uses 250MB,
> >
> > do I
> >
> > > follow the rule proposed here of adding some arbitrary percent of
> >
> > swap, or
> >
> > > do I use the other rule of RAM x 2 up to 200MB? My most important
> >
> > question
> >
> > > is WHY WOULD MORE SWAP BE BAD? Are there really inefficiencies with
> >
> > more
> >
> > > swap? Why would 256M of RAM + 20M of swap behave better than 256M of
> >
> > RAM +
> >
> > > 10 gigs of swap? I'm using extreme examples, but I'm just trying to
> >
> > wrap
> >
> > > my head around why there is a cap to the amount of swap you would
> >
> > want
> >
> > > (other than the fact you've got limited hard disk real estate, but
> >
> > assume
> >
> > > that wasn't an issue...).
> > >
> > > Thanks again,
> > > Isaac
> > >
> > > Quoting Travis Olds <[EMAIL PROTECTED]>:
> > > > On Fri, 17 Aug 2001 [EMAIL PROTECTED] wrote:
> > > > > This has me curious. If I don't need much swap, should I not
> >
> > make
> >
> > > > much swap?
> > > >
> > > > > Or is there no upper limit? If it's the more the marrier, why
> >
> > not
> >
> > > > always just
> > > >
> > > > > make, say, 500MB?
> > > >
> > > > The point of swap space is to allow you to have more programs
> > > > `running'
> > > > than you can actually fit in your physical memory. If you have
> >
> > swap,
> >
> > > > when
> > > > you exaust all of your physical memory the OS can "swap to disk"
> >
> > those
> >
> > > > bits of memory that are not actually being accesses. In this way
> >
> > the
> >
> > > > fact
> > > > that they are not in physical memory and are on slow disk doesn't
> > > > matter
> > > > because that bit of memory is not being accessed. When it does need
> >
> > to
> >
> > > > be
> > > > accessed it gets swapped back in and seomething else is swapped
> > > > out.
> > > >
> > > > Determining th right amount of swap space is really black
> > > > magic. It should be the case that swap + phyical + (some margin of
> >
> > a
> >
> > > > few
> > > > %) = the total amount of memory used by all applications you might
> >
> > wish
> >
> > > > to
> > > > have running at the one time. If you've already got a linux box
> >
> > then
> >
> > > > just
> > > > try opening up everything you might ever want opened at once,
> >
> > check
> >
> > > > the
> > > > momory consumption, add a few % to this number, and that should be
> > > > about
> > > > your total swap + physical memory number.
--
Sridhar Dhanapalan.
"There are two major products that come from Berkeley:
LSD and UNIX. We don't believe this to be a coincidence."
-- Jeremy S. Anderson
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