FW: [olug] Possible error message

[Brian Wiese]

Good point, might want to periodically check the swap freespace in
megabytes (free -m) to find out if it is ever being used.  Is this an
accurate way to measure it's use?

On Tue, 06 May 2003 21:14:48 -0500
Phil Brutsche <phil at brutsche.us> wrote:

|Trent Melcher wrote:
|> 
|> -----Original Message-----
|> From: Trent Melcher [mailto:tmelcher at trilogytel.com] 
|> Sent: Tuesday, May 06, 2003 8:26 PM
|> To: 'CM Miller'
|> Subject: RE: [olug] Possible error message
|> 
|> 
|> Yes, the gerenal rule of thumb is usually double the amount of RAM you
|> have for swap.
|
|That's an old rule of thumb that really doesn't necessarily apply to 
|modern systems.  VM subsystems have improved quite a bit since the 1980s
|:)
|
|Does a Linux firewall with 32 MB - one that's not running squid :) - 
|REALLY need ANY swap, much less 64MB?  NO
|
|Does that database server with 2GB RAM REALLY need that 4GB swap?  Well, 
|maybe it does...
|
|Does a workstation (ie MINE!) with 1GB+ RAM REALLY need 2GB+ swap?  NO
|
|Does having swap help performance?  YES (at least, I've heard it does 
|under Linux, I've never run without swap to find out)
|
|YMMV, of course.  It all depends on the situation, and most of the ones 
|I run into you do NOT *need* 2x RAM for swap.  99% of the time it's too 
|much for the application (ie it's wasted disk space because it's never 
|used), and the rest of the time it's way too little (mostly because the 
|machine's owner doesn't want to spend the $35 to get that extra Crucial 
|256MB DDR266).
|
|> I cant remember exactly, but there is a 4 GB limitation for 32bit
|> processors, it either on physical RAM or Virtual RAM, it may be both,
|> havent looked it up in a while.
|
|Without PAE, 4GB physical; 36GB physical with PAE.  PAE is this feature 
|on PPro (maybe PII) and newer CPUs that changes memory addressing a 
|little bit (36-bit addresses instead of 32-bit).
|
|64GB total available address space.
|
|That's with 32-bit ix86 processors, of course :)
|
|-- 
|
|Phil Brutsche
|phil at brutsche.us
|
|
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  Brian Wiese | bwiese at cotse.com | aim: unolinuxguru
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