AW:Re: [ILUG] Ram swap

[p.slabiak at linux-services.org]

Hi Mike,

the issue is about the sap or weblogic  serverwith at least 4 gb ram...in the first case we have ony 2gb swap (sles8, kernel 2.4.x).In my opinion that's not enough....


>p.slabiak at linux-services.org wrote:
>> Hi all,
>>
>> in the former linux versions (kernel 2.4.x) the relationship beetwen ram and swap was 1:2. Is it the same with kernel 2.6.x ? I use to install (for me) systems with 2.6 kernel in certain relationship swap/ram
>> 1.5:1 but some guys from management want to know exactly.....;=))
>>
>> thank you very much in advance 
>>
>>   
>To an extent, subject to limitations of OS, it depends on use of 
>Computer and the amount of RAM.
>
>When my server had only 12MByte, the paging was very very important.
>
>A 1999 Redhat or NT4 might have been fine with 64M RAM and 64M SWAP.
>
>Going less than 1:1 (or even 1:0)  on most OS, that have LOTS of RAM 
>ought to be possible, but for Mortals with LOTS* of RAM the limit is 1:1 
>unless you really really understand what you are doing.
>
>basic Fileserver may be delirious with only 128M  RAM  but shiny Ubuntu 
>desktop with  several OS in Virtual Machines could be very short of RAM 
>at 4GByte...
>
>
>Actually having to use Swap dramatically slows any system. A 4 or 5 
>Drives striped with a HW RAID controller can speed Swap speed on a 
>multiused fileserver by x100.
>
>So the answer is it is not anything to do with kernel version per se, 
>but how much RAM you have and what is running.
>
>-- 
>Mike
Mit freudlichen Gruessen

Kind regards
--
Pawel Slabiak 
Linux Services
Systemengineer
http://www.linux-services.org
mail: p.slabiak at linux-services.org

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