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Subject: Re: SCSI, U2W in particular?, and poor performance...
From: Justin Robertson (zululinux.com)
Date: Sun Mar 05 2000 - 01:45:30 CST

I Fail to see what that has to do with it...
The entire point I'm trying to make here is that faster hardware is
running slower, and I'd like to find out why. Now it's not a case of me
having b0rked hardware, because I've had other people experience the same
'issue' on SCSI drives vs IDE drives. What specificly is it that is
handled so differently between the two that would slow down mail transfer
so intensly. The reason I say it's SCSI, is SCSI is the only common factor
between some of the boxes this has been tried on and slow, and all the IDE
boxes, even when I place an IDE drive into the machine in question, seem
to yeild better performance...

Justin Robertson
<zululinux.com>

On Sun, 5 Mar 2000, Rafi Sadowsky wrote:

>
>
> On Sat, 4 Mar 2000, Wietse Venema wrote:
>
> > Well let it be said that it is not possible to safely (*) create
> > 1024 files in 2 seconds on today's IDE disks with a non-journaling
> > file system. Doing so requires a multiple of 1024 disk updates in
> > different places (directory blocks, file blocks, inode blocks),
> > and disks just ain't that fast. At 10kRPM you have 3ms average
> > rotational latency. You can do the math.
> >
> > Wietse
> >
> > (*) safely as in: should someone pull the plug the files must not
> > be lost. In other words, Linux may have told you that the files
> > are on disk, but in reality they aren't. Use a real file system
> > for Postfix if you care about reliability.
>
> specifically for Linux: wouldn't "chattr +S" ( as implemented in
> "postfix-script" ) fix this problem ?
>
> rather strange though it Linux syslogging is synchronous by default - no ?
>
> Rafi
>
>