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2009/10/20 James Cameron 
> On Tue, Oct 20, 2009 at 09:39:50AM +0800, Ray Rashif wrote:

quoted text
> > Since on a Linux system files are written to almost every minute,

> > recording atime everytime an access occurs increases the disk I/O.

>

> I'm not sure that is right; the way you put it.

>

> Perhaps you mean "Since on a Linux system files are read from almost

> every minute, recording atime every time a read occurs increases the

> write disk I/O."

>

> atime on a file is changed whenever the file is read.  The change is

> buffered in memory for a while; usually no more than a minute, then is

> written out to disk.

>

> So atime causes at least one disk write I/O for a set of disk read I/Os.

>

> It certainly does impact performance ... if it is not needed.

>

> > I need to know access times for some files so I don't quite like that.

> > I use relatime: http://kerneltrap.org/node/14148

>

> Another method is to place these files in a separate filesystem with

> atime enabled.

I actually meant to type "read from", but thanks for correcting :)
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2009/10/20 James Cameron <quozl@us.netrek.org>
On Tue, Oct 20, 2009 at 09:39:50AM +0800, Ray Rashif wrot=

e:

quoted text
> Since on a Linux system files are written to almost every minute,

> recording atime everytime an access occurs increases the disk I/O.

I'm not sure that is right; the way you put it.
Perhaps you mean "Since on a Linux system files are read from almost

every minute, recording atime every time a read occurs increases the

write disk I/O."
atime on a file is changed whenever the file is read. =A0The change is

buffered in memory for a while; usually no more than a minute, then is

written out to disk.
So atime causes at least one disk write I/O for a set of disk read I/Os.
It certainly does impact performance ... if it is not needed.
> I need to know access times for some files so I don't quite like t=

hat.

quoted text
> I use relatime: http://kerneltrap.org/node/14148

Another method is to place these files in a separate filesystem with<=

br>

atime enabled.I actually meant to type &qu=

ot;read from", but thanks for correcting :) =A0
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