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Re: opinions on swap size and usage?

On Tuesday 12 February 2002 10:57 am, Jeff S Wheeler wrote:
> Alexis Bory's post earlier today made me think about swap a bit more
> than I usually do.  What do other folks on this list do?  Zero swap?  As
> much swap as physical memory?  More?  Why?  Can you change the swapper's
> priority, and does this help when your machine starts swapping heavily?

I run 1GB memory in almost all my new servers.  I always leave some swap 
space, depending on use and physical RAM (more use=more RAM=more swap).  Even 
with 1GB RAM, some applications, especially Oracle, still swap occasionally.  
For instance, here are two of my servers right now (srv0 is Oracle server; 
srv1 is Apache):

[michael@srv0 michael]$ free
             total       used       free     shared    buffers     cached
Mem:       1036352     454400     581952    2144080      62264      52388
-/+ buffers/cache:     339748     696604
Swap:       783216      57632     725584
[michael@srv0 michael]$ uptime
 11:40am  up 26 days, 23:17,  2 users,  load average: 0.05, 0.03, 0.00

[michael@srv1 michael]$ free
             total       used       free     shared    buffers     cached
Mem:        517340     266344     250996      91956     163004      23692
-/+ buffers/cache:      79648     437692
Swap:       128480       9376     119104
[michael@srv1 michael]$ uptime
 11:40am  up 26 days, 23:13,  2 users,  load average: 0.00, 0.05, 0.56

I have never seen it recommended practice to use no swap, although it is 
becoming a very common practice these days.  I think that is very dangerous, 
on a server.  It may be permissible on a desktop with plenty of RAM, but I 
still have 1GB RAM + 1GB swap on my main desktop and 512MB RAM + 512MB swap 
on this desktop (though I've never seen swap used. Just in case...)

There's my opinion, backed up by what I use daily.  :-)
 Michael Merritt                    O2/CO2 Conversion Specialist [o]
 michael@miklm.com | www.miklm.com | (931) 205-1392 | AIM/MSN miklm
 "Piracy is not a technological issue. It's a behavior issue."   
                                                       --Steve Jobs

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