IDS Forum

Re: IDS 7.31 Solaris8 - Long Checkpoints

Posted By: Art Kagel
Date: Monday, 16 March 2009, at 12:42 p.m.

In Response To: Re: IDS 7.31 Solaris8 - Long Checkpoints (kate)

Comments below:

Art

On Mon, Mar 16, 2009 at 12:20 PM, kate <kate@iiug.org> wrote:

> To shorten checkpoints in version 7.31 you should
>
> 1) increase the checpoint interval to 500sec (you don't want the interval
> to
> ever force the checkpoint)

I STRONGLY disagree. You ONLY want your checkpoints triggered by the
CHKPTINTVL not by the physical log reaching 75%! Letting that failsafe
trigger regularly is dangerous. If the checkpoint is slow and the physical
log should fill to 100% before the checkpoint can clear it, the engine is at
risk for data loss if it crashes before the checkpoint completes. Since
many crashes, especially in older buggy versions like 7.31UD1 that the OP is
using, occur during periods of stress, you can't discount the danger.

>
>
> 2) lower the lru_max_dirty to 2
> 3) lower the lru_min_dirty to 1

I agree with this obviously, but, my point of increasing the number of LRUs
and CLEANERS is that if you are going to be flushing more frequently between
checkpoints you have to provide the resources to do that. Spreading the
buffers across more LRU queues will reduce the number of buffers that need
to be flushed at any one time spreading the overhead out more smoothly.

>
>
> Try this out.
>
> I assume you are using KAIO and that is why the NUMAIOVP is set to 1? Do an
> >onstat -g iov to verify this.

DAMN, I missed that. Good catch Kate. If the OP is using COOKED files,
then this may be the one BIGGEST cause for the slow checkpoints! In that
case, with 7.31, they should have at least 2 AIO VPs configured per chunk to
minimize checkpoint duration.

Even if he is not, he should have at least 2 and perhaps as many as 6 AIO
VPs just to handle cooked io to the message and console logs and other
similar IO (sqexplain files, etc.).

Art

>
>
> Thanks!
> Kate Tomchik [ kate@iiug.org ] www.iiug.org
> International Informix Users Group Board of Directors
>
> A computer lets you make more mistakes faster than any invention in human
> history - with the possible exceptions of handguns and tequila.
> Mitch Ratliffe
>
> ---------- Original Message -----------
> From: "KURT VAN GOMPEL" <kvangompel@caami-hziv.fgov.be>
> To: ids@iiug.org
> Sent: Mon, 16 Mar 2009 11:26:19 -0400 (EDT)
> Subject: IDS 7.31 Solaris8 - Long Checkpoints [15147]
>
> > Hello,
> >
> > We are running IDS7.31 UD1 on a Solaris8 server with 2 Sparc64
> > processors and 4GB RAM. It is used for interactive and batch
> > processing. When lots of manipulations on the DB are done, it takes
> > sometimes more than 60 seconds to do his checkpoints. Some
> > parameters of our config file: MULTIPROCESSOR 1 NUMCPUVPS 2
> > SINGLE_CPU_VP 0 NOAGE 1 AFF_SPROC 0 AFF_NPROCS 0 LOCKS 700000
> > BUFFERS 100000 NUMAIOVPS 1 PHYSBUFF 64 LOGBUFF 64 LOGSMAX 600
> > CLEANERS 8 CKPTINTVL 120 LRUS 8 LRU_MAX_DIRTY 5 LRU_MIN_DIRTY 2
> >
> > Any idea how to speed up the checkpoints?
> >
> >
>
> *****************************************************************************
> ** Forum Note: Use "Reply" to post a response in the discussion forum.
> ------- End of Original Message -------
>
>
>
> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

--
Art S. Kagel
Oninit (www.oninit.com)
IIUG Board of Directors (art@iiug.org)

Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Oninit, the IIUG, nor any other organization
with which I am associated either explicitly or implicitly. Neither do
those opinions reflect those of other individuals affiliated with any entity
with which I am affiliated nor those of the entities themselves.

--0016364ee022480d3c04653f23a2

Messages In This Thread

• IDS 7.31 Solaris8 - Long Checkpoints
  KURT VAN GOMPEL -- Monday, 16 March 2009, at 11:26 a.m.
  • RE: IDS 7.31 Solaris8 - Long Checkpoints
    Norma Jean Sebastian -- Monday, 16 March 2009, at 11:32 a.m.
    • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
      KURT VAN GOMPEL -- Monday, 16 March 2009, at 11:35 a.m.
      • RE: RE: IDS 7.31 Solaris8 - Long Checkpoints
        Norma Jean Sebastian -- Monday, 16 March 2009, at 11:56 a.m.
        • RE: RE: IDS 7.31 Solaris8 - Long Checkpoints
          kate -- Monday, 16 March 2009, at 12:24 p.m.
          • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
            Art Kagel -- Monday, 16 March 2009, at 12:35 p.m.
            • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
              kate -- Monday, 16 March 2009, at 12:46 p.m.
              • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                Art Kagel -- Monday, 16 March 2009, at 12:54 p.m.
                • RE: RE: IDS 7.31 Solaris8 - Long Checkpoints
                  Norma Jean Sebastian -- Monday, 16 March 2009, at 1:58 p.m.
                  • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                    Art Kagel -- Monday, 16 March 2009, at 3:19 p.m.
                    • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                      KURT VAN GOMPEL -- Monday, 16 March 2009, at 3:38 p.m.
                      • Re: IDS 7.31 Solaris8 - Long Checkpoints
                        tilleul17@web.de -- Monday, 16 March 2009, at 4:06 p.m.
                      • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                        Art Kagel -- Monday, 16 March 2009, at 6:56 p.m.
                        • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                          KURT VAN GOMPEL -- Tuesday, 17 March 2009, at 5:29 a.m.
                          • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                            Art Kagel -- Tuesday, 17 March 2009, at 10:28 a.m.
                            • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                              KURT VAN GOMPEL -- Tuesday, 24 March 2009, at 9:33 a.m.
                              • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                                Art Kagel -- Tuesday, 24 March 2009, at 10:34 a.m.
                                • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                                  PING TANG -- Tuesday, 24 March 2009, at 11:45 a.m.
                              • Re: RE: IDS 7.31 Solaris8 - Long Checkpoints
                                Art Kagel -- Tuesday, 24 March 2009, at 10:36 a.m.
  • Re: IDS 7.31 Solaris8 - Long Checkpoints
    Art Kagel -- Monday, 16 March 2009, at 11:51 a.m.
  • Re: IDS 7.31 Solaris8 - Long Checkpoints
    kate -- Monday, 16 March 2009, at 12:20 p.m.
    • Re: IDS 7.31 Solaris8 - Long Checkpoints
      Art Kagel -- Monday, 16 March 2009, at 12:42 p.m.
      • Re: IDS 7.31 Solaris8 - Long Checkpoints
        kate -- Monday, 16 March 2009, at 12:45 p.m.
  • Re: IDS 7.31 Solaris8 - Long Checkpoints
    kate -- Tuesday, 17 March 2009, at 9:43 a.m.

IDS Forum is maintained by Administrator with WebBBS 5.12.