Bruce Momjian <[EMAIL PROTECTED]> wrote:
>> > Yes, this double-writing is a problem. Suppose you have your WAL on a
>> > separate drive. You can fsync() WAL with zero head movement. With a
>> > log based file system, you need two head movements, so you have gone
>> > from zero movements to two.
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> I got some information from Stephen Tweedie on this - please keep him
> "Cc:" as he's not on this list
>
>
> Bruce Momjian <[EMAIL PROTECTED]> writes:
>
> > I was talking
> Hi,
>
> On Fri, May 04, 2001 at 01:49:54PM -0400, Bruce Momjian wrote:
> > >
> > > Performance doing what? XFS has known performance problems doing
> > > unlinks and truncates, but not synchronous IO. The user should be
> > > using fdatasync() for databases, btw, not fsync().
> >
> > This i
I got some information from Stephen Tweedie on this - please keep him
"Cc:" as he's not on this list
Bruce Momjian <[EMAIL PROTECTED]> writes:
> I was talking to a Linux user yesterday, and he said that performance
> using
> > Yes, this double-writing is a problem. Suppose you have your WAL on a
> > separate drive. You can fsync() WAL with zero head movement. With a
> > log based file system, you need two head movements, so you have gone
> > from zero movements to two.
>
> It may be worse depending on how the fi
* Bruce Momjian <[EMAIL PROTECTED]> [010502 15:20] wrote:
> > The "problem" with log based filesystems is that they most likely
> > do not know the consequences of a write so an fsync on a file may
> > require double writing to both the log and the "real" portion of
> > the disk. They can also ex
* Bruce Momjian <[EMAIL PROTECTED]> [010502 14:01] wrote:
> I was talking to a Linux user yesterday, and he said that performance
> using the xfs file system is pretty bad. He believes it has to do with
> the fact that fsync() on log-based file systems requires more writes.
>
> With a standard B
> The "problem" with log based filesystems is that they most likely
> do not know the consequences of a write so an fsync on a file may
> require double writing to both the log and the "real" portion of
> the disk. They can also exhibit the problem that an fsync may
> cause all pending writes to
