Subject: Re: processes consuming all CPU during I/O on LFS
To: None <tls@rek.tjls.com>
From: matthew sporleder <msporleder@gmail.com>
List: current-users
Date: 11/17/2006 09:24:36
On 11/16/06, Thor Lancelot Simon <tls@rek.tjls.com> wrote:
> On Thu, Nov 16, 2006 at 03:28:29PM -0500, Blair Sadewitz wrote:
> >
> > I've noticed that if I untar a lot of files on an LFS filesystem,
> > toward the very end of the untar (when all files in the archive are
> > listed with -v but before it finishes), tar consumes 95%+ CPU for a
> > few minutes and things get VERY slow.  This does not happen on FFS
> > filesystems.  Is this just the nature of LFS, a bug, or do I have
> > something set up incorrectly?  I got my lfs bsize from the -A option
> > (2949k).
>
> It's a problem with the code that flushes pending writes.  Your system
> has a lot of free RAM, I expect.
>

Is there a good way to tune the flusher?
This is a common problem for solaris servers and here's an example of
the solaris docs for it:
http://docs.sun.com/app/docs/doc/817-0404/6mg74vs9i?q=tunables&a=view