[CentOS] Swap: typical rehash. Why?

[Sam Drinkard]

William L. Maltby wrote:

>I can't resist. Read the thread that was pointed to on lkml. ROTFLMAO.
>
>*Real* UNIX addressed these problems long ago. I guess the "Gurus"
>suffer from NIH (Not Invented Here) syndrome.
>
>Given a "general purpose" system, tunability is a must. UNIX, as
>delivered by USL in such examples as Sys V, had tunables that let admins
>tune to their needs. A single "swappiness" value is woefully inadequate.
>
>Among the tunables were how much memory for cache, how much for buffers,
>how much for X/Y/Z, high and low water marks for all sorts of memory
>related stuff and a very valuable attribute bit for executables called
>the "sticky bit". It is not the "sticky bit" as used now. It said lock
>this app in memory and never swap it. A variation on that (couldn't keep
>original semantics with the size of apps these days) would address some
>of the "responsiveness" issues raised by some. Some admin tunables would
>address the other issues.
>
>The "Gurus" need to learn something my father taught me. "A smart man
>learns from his mistakes. A wise man learns from the mistakes of
>others". I'm really smart. :-(  And, apparently, so are the "Gurus". To
>think they have VM this long and no one has thought to swipe these good
>ideas from real UNIX. And they're still argueing about all that as if it
>has never been hashed out and addressed before.
>  
>
When I started out in UNIX, it was Interactive 1.3, if I remember, and 
it was a dog.  Coming from a DOS world, I guess I was overwhelmed by all 
the things that could be tuned in the kernel.  I probably didn't learn 
much about them then, and still don't know a lot about it, but unless 
you actively try some of the suggestions and see how things work or 
behave, then I guess you still don't know.  There seems to have been 
some built in tradeoffs over the course of the years in the unix-like 
OS's, but it's still seems to work the same.  I wonder how well 
Interactive 3.4 would stack up to today's versions of CentOS, all the 
*BSD's and such. 

-- 
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