[Ocfs2-users] Anyone have an idea how to find file i/othroughput?

[Ulf Zimmermann]

I will look at it. In the meanwhile I did find at least one of the
standby processes reading in bursts every 60-70 seconds like 400MB in
14.xx seconds from control01.ctl, even that file is only 94MB large.

> -----Original Message-----
> From: Andrew Phillips [mailto:Andrew.Phillips at betfair.com]
> Sent: Tuesday, February 19, 2008 01:43
> To: Ulf Zimmermann
> Cc: ocfs2-users at oss.oracle.com
> Subject: RE: [Ocfs2-users] Anyone have an idea how to find file
> i/othroughput?
> 
> Ulf,
> 
>   Have you considered using systemtap? There is a recipe here that
could
> be used to find out whats going on;
> 
> http://sourceware.org/systemtap/wiki/WSDeviceMonitor?highlight=%28%
> 28WarStories%29%29
> 
>    I'm not sure how well that would work with ocfs2. Unlike dtrace,
> systemtap can be more "uneven" in coverage. Its also something that
> requires a bit of fiddling (installing debuginfo packages).
> 
>    The recipe above traps vfs_read and vfs_write so should work as a
> first stab at identifying the process id thats causing the I/O.
> 
>    I'd also advise some thought if its to be used on a production
> environment. Having said that, I've used it on a production oracle RAC
> database server and found it very valuable.
> 
>    I don't recall you mentioning the distribution, but RH, CentOS, and
> oracle's version of CentOS should all work.
> 
>    As always, read the instructions on the label, etc...
> 
>      Andy
> 
> 
> On Mon, 2008-02-18 at 23:14 -0800, Ulf Zimmermann wrote:
> > Forgot to mention, this remote server is just Oracle. It has one
standby
> > database and one local database, the local one is suppose to be
idle,
> > i.e. nothing connecting to it, besides once in a while for available
> > check.
> >
> > While the primary database of the standby was down, I saw less disk
read
> > access, but every 5 minutes for about 60 seconds I would see
> > 50-60MB/sec. After the primary came back up, read access is as high
as
> > 160MB/sec.
> >
> > We are only seeing it on this single node of the remote standby. The
> > local standby (on EXT3) is not doing the same thing.
> >
> > > -----Original Message-----
> > > From: Sunil Mushran [mailto:sunil.mushran at oracle.com]
> > > Sent: Monday, February 18, 2008 19:28
> > > To: Ulf Zimmermann
> > > Cc: ocfs2-users at oss.oracle.com
> > > Subject: Re: [Ocfs2-users] Anyone have an idea how to find file
i/o
> > > throughput?
> > >
> > > If a userspace process is behind the io surge, then strace should
> > help.
> > > But determining the process may require a bit of trial and error.
> > >
> > > Ulf Zimmermann wrote:
> > > > We got a remote Oracle 10g R2 standby running on OCFS2. Initial
when
> > we
> > > > started the standby, read I/O was < 5MB/sec on average. Since
then
> > it
> > > > has grown to over 40MB/sec (longer average, it peaks much
higher).
> > Here
> > > > is a graph showing this:
> > > >
> > > > http://www.alameda.net/~ulf/dbphx01.png
> > > >
> > > > We also have a local standby running (on EXT3) which is not
showing
> > the
> > > > same symptom. I am trying to find where all these reads are
> > happening.
> > > > Anyone have an idea how to figure that out on Linux?
> > > >
> > > > Ulf.
> > > >
> > > >
> > > > _______________________________________________
> > > > Ocfs2-users mailing list
> > > > Ocfs2-users at oss.oracle.com
> > > > http://oss.oracle.com/mailman/listinfo/ocfs2-users
> > > >
> >
> >
> > _______________________________________________
> > Ocfs2-users mailing list
> > Ocfs2-users at oss.oracle.com
> > http://oss.oracle.com/mailman/listinfo/ocfs2-users
> 
>
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