Re: 11g RedHat 5 and Hugepages

  • From: "dbvision@xxxxxxxxxxxx" <dbvision@xxxxxxxxxxxx>
  • To: Jon.Crisler@xxxxxxx, tgascard@xxxxxxxxx, Kevin Closson <ora_kclosson@xxxxxxxxx>
  • Date: Wed, 13 Oct 2010 14:31:39 +0800

Beg to disagree there, Kevin.  Hugepage setup - in Linux, mind you - is more a
hindrance than an advantage until one starts to talk about SGA sizes of much 
more
than a couple GBs.  

Hardly possible in 32-bit OS's, where with luck one gets an SGA of 2GB, if that.
Of course I'm not including things like Wintel's weird windowed large memory
handling for 32-bit Windows. Not even sure if that one is handled with a TLB,
looks like the old PC Expanded memory?

Systems with large connection counts nowadays are handled with pooled 
connections
in 99% of the cases. I've lost memory of the last application server I've seen
that didn't use some form or other of that for large number of connections.  And
there is always MTS/Shared connection/whatever-its-name-is-nowadays. :)

Don't get me wrong, though: I've been asking folks for a long time to use
hugepages with 64-bit OS's.  No doubt whatsoever in my mind it has an advantage
for the larger SGA sizes so common in those.  In fact, I'm continually surprised
it's not a default setup for Oracle in 64-bit OS's!

Cheers
Nuno

On Wed Oct 13  2:26 , Kevin Closson  sent:

>Also, this notion that 32bit OS deployments don't need hugepages is quite 
>wrong.
Any system with large connection count is not going to be able to afford the
wasted page table memory.
>
>Use hugepages.

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