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

From: David Miller <David.J.Miller_at_Sun.COM>
Date: Fri, 31 Jul 2009 09:26:07 -0500
Message-id: <4A72FEFF.90308_at_Sun.COM>

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?


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:
> [] On Behalf Of Crisler, Jon
> Sent: Wednesday, July 29, 2009 10:43 AM
> To: Don Seiler;
> Cc:
> Subject: RE: Solaris 10 and Oracle 10g - swap space problem
> Yes, I do have sga_max_size set.
> -----Original Message-----
> From: Don Seiler []
> Sent: Wednesday, July 29, 2009 7:54 AM
> To:
> Cc: Crisler, Jon;
> 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.
> --

Received on Fri Jul 31 2009 - 09:26:07 CDT

Original text of this message