Very Computer

by **Mohammed Saji** » Sat, 23 Nov 2002 03:57:06

Hi There,

I have a SUN E3000 server with 6 .8 GB allocated as swap slice but when I
check swap with swap -l it shows only 2 GB. Any idea why?

Thanks in advance

Sajid

by **Darren Dunha** » Sat, 23 Nov 2002 04:21:59

> Hi There,
> I have a SUN E3000 server with 6 .8 GB allocated as swap slice but when I
> check swap with swap -l it shows only 2 GB. Any idea why?

Likely you are running a 32 bit kernel.

1) Are you running 2.6 or below?
1a) If not, do a 'isainfo -b'

32 bit kernels can only use the first 2GB of any swap file. So you're
wasting 4.8 GB with this configuration.

Do you *need* more than a 2GB swapfile on this machine? Why are you
paging/swapping so much?

--

Unix System Administrator Taos - The SysAdmin Company
Got some Dr Pepper? San Francisco, CA bay area
< This line left intentionally blank to confuse you. >

by **Chris Thomps** » Sat, 23 Nov 2002 04:34:27

>I have a SUN E3000 server with 6 .8 GB allocated as swap slice but when I
>check swap with swap -l it shows only 2 GB. Any idea why?

You are probably running an old version of Solaris (2.6 or earlier) or
a 32-bit mode kernel. In these cases only the first 2 GB of each swap
area can be used.

Chris Thompson
Email: cet1 [at] cam.ac.uk

by **msajid** » Wed, 27 Nov 2002 04:00:54

Hi there,

Right I was having 2.6 and recently upgraded to 8 but still in 32
bit mode. I am going to do the OBP upgrade this weekend. Thanks for
this info.

Actually, I am not sure whether I will need so much swap but this has
been proposed by my application vendor. My system has 2 GB RAM . There
is one Oracle instance ( Oracle 7 ) already running. We need to have one
more instance ( Oracle 8 ) on the same machine for application
co-existance. This is one reason I thought it might require more swap.
Application is one of oil field related ( Seismic ) applcations which
also reserves swap space when executed.

Any comments? Or what kind of swap size is optimal on a 2 CPU , 2
GB machine?

Thanks once again.

--
Posted via http://dbforums.com

by **Darren Dunha** » Wed, 27 Nov 2002 06:31:20

> Any comments? Or what kind of swap size is optimal on a 2 CPU , 2
> GB machine?

Required swap size depends on what you're doing, not just what you have.

If you're trying to run 3 GB of stuff on 2GB of RAM, then you're going
to need swap space (and you know it will slow down).

If you're only running 1GB of stuff on 1GB of RAM, then you may not need
any swap, but having at least a bit turned on can improve things.

Of course your swap space is also your default dump region, so you may
want to have it if you need core dumps.

Most production machines need speed, so swapping/paging of any
significant amount is a very bad thing. They don't tend to need gigs
and gigs of swap space.

Adding more swap space isn't really a bad thing other than the loss of
disk space. I'm *not* giving a 10G machine a 10G swap space unless
someone has a good reason for it. I'll generally default to 2G when I
have no other information.

--

Unix System Administrator Taos - The SysAdmin Company
Got some Dr Pepper? San Francisco, CA bay area
< This line left intentionally blank to confuse you. >

Very Computer

Swap space not show by swap -l

Swap space not show by swap -l

Swap space not show by swap -l

Swap space not show by swap -l

Swap space not show by swap -l

Swap space not show by swap -l