Re: how much swap for 10g on a 4Gb RAM system?
From: DA Morgan <damorgan_at_psoug.org>
Date: Thu, 31 Jul 2008 17:12:18 -0700
Message-ID: <1217549532.448849@bubbleator.drizzle.com>
>> On Jul 29, 12:19 pm, Palooka <nob..._at_nowhere.com> wrote:
>>> obakesan wrote:
>>>> Hi
>>>> I'm just going through installing 10g and wondered about the swap
>>>> requirements. The documents I'm reading suggest:
>>>> " Swap space should be twice the amount of RAM for systems with 2GB of
>>>> RAM or less and between one and two times the amount of RAM for
>>>> systems with
>>>> more than 2GB. "
>>>> Since I've got 4 Gig, do I really need 4Gig of Swap? I'm not
>>>> pressing this
>>>> system as its just a "learning" platform.
>>>> Has anyone got any experience with trying this with less:
>>>> $ grep -i swaptotal /proc/meminfo
>>>> SwapTotal: 2031608 kB
>>> Surely it can't hurt just to follow the instructions, can it?
>>>
>>> Palooka
>>
>> Yes, it can. It can hurt a lot. That's why the instructions change
>> over time, and sometimes do not reconcile between release notes,
>> installation guides and metalink notes. Platform specific issues can
>> be especially irritating, and the range of configuration issues over
>> various linux releases is quite broad.
>>
Date: Thu, 31 Jul 2008 17:12:18 -0700
Message-ID: <1217549532.448849@bubbleator.drizzle.com>
Palooka wrote:
> joel garry wrote:
>> On Jul 29, 12:19 pm, Palooka <nob..._at_nowhere.com> wrote:
>>> obakesan wrote:
>>>> Hi
>>>> I'm just going through installing 10g and wondered about the swap
>>>> requirements. The documents I'm reading suggest:
>>>> " Swap space should be twice the amount of RAM for systems with 2GB of
>>>> RAM or less and between one and two times the amount of RAM for
>>>> systems with
>>>> more than 2GB. "
>>>> Since I've got 4 Gig, do I really need 4Gig of Swap? I'm not
>>>> pressing this
>>>> system as its just a "learning" platform.
>>>> Has anyone got any experience with trying this with less:
>>>> $ grep -i swaptotal /proc/meminfo
>>>> SwapTotal: 2031608 kB
>>> Surely it can't hurt just to follow the instructions, can it?
>>>
>>> Palooka
>>
>> Yes, it can. It can hurt a lot. That's why the instructions change
>> over time, and sometimes do not reconcile between release notes,
>> installation guides and metalink notes. Platform specific issues can
>> be especially irritating, and the range of configuration issues over
>> various linux releases is quite broad.
>>
> Joel, > > I confess to being a little surprised at this. If Oracle say double the > RAM, why not just do so? A few gig of disk space is surely neither here > nor there nowadays. Can you elucidate? > > Palooka
Because sometimes throwing more resources at a problem makes it worse. Jonathan Lewis has a great example he uses where increasing sort area causes more memory to be swapped to disk: Not a good thing. There are many other case study examples of this behavior.
-- Daniel A. Morgan Oracle Ace Director & Instructor University of Washington damorgan_at_x.washington.edu (replace x with u to respond) Puget Sound Oracle Users Group www.psoug.orgReceived on Thu Jul 31 2008 - 19:12:18 CDT