Re: 11g RedHat 5 and Hugepages
- From: Kevin Closson <ora_kclosson@xxxxxxxxx>
- To: Oracle-L@xxxxxxxxxxxxx
- Date: Wed, 13 Oct 2010 07:56:00 -0700 (PDT)
Nothing wrong with this feedback because it includes information about how to
do
it right (e.g., pooled connections). But therein lies my point. Take you 1GB
SGA
and attach a couple hundred dedicated connection and you'll wish you'd have
either a) used huge pages or b) reduced your dedicated connection count. I
wrote:
"Any system with large connection count is not going to be able to afford the
wasted page table memory."
So, while this is a good follow up it isn't disagreeing at all with what I am
said.
Oh, by the way, why on earth would anyone still be using a 32-bit OS? That is a
larger question.
In summary, if you don't like the size of the page tables do something about
it.
________________________________
From: "dbvision@xxxxxxxxxxxx" <dbvision@xxxxxxxxxxxx>
To: Jon.Crisler@xxxxxxx; tgascard@xxxxxxxxx; Kevin Closson
<ora_kclosson@xxxxxxxxx>
Cc: Oracle-L@xxxxxxxxxxxxx
Sent: Tue, October 12, 2010 11:31:39 PM
Subject: Re: 11g RedHat 5 and Hugepages
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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