Problem with adding more swap !

[Supote Leelasupphakorn]

Hi, 

  I've heard if there are many disks on one machine
it's good (in respect of performance) for adding swap
parition on multiple drive, what does this mean
(if that's true) ?

  My box has six IDE drives two on primary, two on 
secondary and two connected via IDE controller.

TIA,
pjn


 --- Jerry McAllister <jerrymc at clunix.cl.msu.edu> wrote: > > 
> > Hi, all
> > 
> >    The documents on freebsd's website suggest that,
> > as a system grows, it's recommended for adding more
> > swap paritition to system. My questions are: Does
> > it mean adding another swap to disk or to slice ?
> > 
> > 
> > The disk structure: 
> > 
> >         ad0s1 --> ad0s1a   /      (boot from here)
> >               --> ad0s1b   swap
> >               --> ad0s1e   /var
> >               --> ad0s1f   /tmp
> >               --> ad0s1g   /usr
> > 
> >         ad0s2 --> ad0s2e   /usr1  (data)
> > 
> > Do I need to add another swap partition as "ad0s2b" ?
> 
> Hmmm.   I am not quite sure why you would have made two
> separate
> slices on the one disk for FreeBSD instead of having another
> partition on slice-1, but...
> 
> Anyway, what do you mean 'as a system grows'?   Unless you
> have some
> very memory hungry applications or large numbers of processes
> that 
> hang around but don't really need a lot of processor time,
> generally 
> you figure swap size needs by memory size.   You want at least
> more
> than your physical memory and 2X to 2-1/2X physical memory is
> the
> typical rule of thumb.   If you already meet that, don't worry
> about,
> unless you have some other indication that you are running out
> of
> combined memory/swap (page) space.   NOTE that the virtual
> memory
> system uses swap space for its paging.  Typically, not much
> actual
> swapping really happens, though it can if there are a lot of
> processes
> not doing anything.
> 
> You can make a file pretty much anywhere there is room and set
> things
> up to swap to it, but that should be considered only a
> temporary solution.   
> The better thing is to make either a larger s1b or make an s2b
> partition 
> for swap (or add a disk - ad1s1b, + whatever) as you say.
> 
> In either case (enlarging s1b or making an s2b), unless you
> have space
> left in one of those slices that you did not already use up in
> the
> existing partitions,  it means redoing the filesystems already
> on the 
> slice.  That means backing up everything on the slice,
> repartitioning, 
> newfsing and restoring everything.  So, given this, it would
> probably 
> be a good time to rethink your whole disk layout and go from
> there.
> Maybe it would also be a good time to go to an additional or
> larger
> disk as well.
> 
> ////jerry
> 
> > 
> > TIA,
> > pjn 

________________________________________________________________________
Want to chat instantly with your online friends?  Get the FREE Yahoo!
Messenger http://mail.messenger.yahoo.co.uk