Re: Solaris 10 and Oracle 10g - swap space problem

  • From: David Miller <David.J.Miller@xxxxxxx>
  • To: Jon.Crisler@xxxxxxx
  • Date: Fri, 31 Jul 2009 09:26:07 -0500

Hi Jon,

What version of S10 are you running?  (cat /etc/release).  Depending on
the release, there were some issues related to getting large pages for the
SGA and the page coalescing process can slow things down a lot if there
aren't many large pages available.  There is a Sun Infodoc talking about
that I believe.  I can find it if you can't.

What hardware platform is this?

Swap shouldn't need to be initialized.  It just gets allocated/reserved in
case it's needed.  And that really doesn't take very long, so I can't
believe that's the reason for the slow startup.

How big is your SGA?  Larger SGAs will take longer to start but that's not
related to swap at all.  And if the page coalescing daemon is needed, it
can slow things down even more.

And have you looked at "pmap -xs PID" for the lgwr PID to be sure you're getting
2M (x64) or 4M (SPARC) pages?  Does it say "DISM" or "ISM" for those?

Regards,

Dave Miller

Crisler, Jon wrote, On 07/30/09 09:57:

I played around extensively with sga_max_size, sga_target, DISM and ISM
related settings etc. without success- whatever I do for oracle shared
memory segments gets mapped to swap space.  Also, instance startup seems
to be really slow due to the swap initialization, but once the instance
is running it seems fine.   I have not found much on Metalink addressing
this issue- does anybody have a Metalink or Sun technote that addresses
this issue ?

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Crisler, Jon
Sent: Wednesday, July 29, 2009 10:43 AM
To: Don Seiler; mathias.magnusson@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: RE: Solaris 10 and Oracle 10g - swap space problem
Yes, I do have sga_max_size set. 
-----Original Message-----
From: Don Seiler [mailto:don@xxxxxxxxx] Sent: Wednesday, July 29, 2009 7:54 AM 
To: mathias.magnusson@xxxxxxxxx
Cc: Crisler, Jon; oracle-l@xxxxxxxxxxxxx
Subject: Re: Solaris 10 and Oracle 10g - swap space problem

IIRC, lock_sga isn't valid in Solaris.

Jon, do you have sga_max_size explicitly set?  I seem to recall this
behavior on Solaris 10 when sga_max_size was set explicitly.  It
caused us much grief if we set sga_max_size to more than half of the
total physical memory on the box.

Don.
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