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Date:      Thu, 3 May 2001 22:35:29 -0700
From:      "Ted Mittelstaedt" <tedm@toybox.placo.com>
To:        <robert@mpe.mpg.de>, <freebsd-newbies@FreeBSD.ORG>
Subject:   RE: Survey on tuning facts.
Message-ID:  <001801c0d45c$07603840$1401a8c0@tedm.placo.com>
In-Reply-To: <200105031347.f43DlES30960@robert2.mpe-garching.mpg.de>

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Sadly, the art of tuning UNIX systems is rapidly disappearing
because for one thing so many of the kernel parameters today
are self-tuning, but the biggest reason is that it's easier to
throw money at bigger hardware than to tune the system.

Still, the sync/async/softupdates thing is still very serious
and anyone managing a FreeBSD server needs to know about it.
Beyond that, if your doing some unusual things on your server
you do need to go off the defaults.  For example, on our
Usenet news server, which handles many itty-bitty files, I've
created the spools with a smaller frag size and smaller number of
bytes per inode because you need all those extra inodes on a
newsspool (but, it makes the disks run slower so don't ever do
this on anything other than a newsserver)  Also, for another
example, on a major BGP router with close to 100K routes in it
I had to raise NMBCLUSTERS and VM_KMEM_SIZE as well as MAXUSERS.
But, beyond these things your going to get better tuning results
by good hardware selection, (espically disks) and by recompiling
your kernel to remove unneeded drivers.  If your doing normal things
on your server the defaults will probably serve you best.

Ted Mittelstaedt                      tedm@toybox.placo.com
Author of:          The FreeBSD Corporate Networker's Guide
Book website:         http://www.freebsd-corp-net-guide.com


>-----Original Message-----
>From: owner-freebsd-newbies@FreeBSD.ORG
>[mailto:owner-freebsd-newbies@FreeBSD.ORG]On Behalf Of Robert Suetterlin
>Sent: Thursday, May 03, 2001 6:47 AM
>To: freebsd-newbies@FreeBSD.ORG
>Subject: Survey on tuning facts.
>
>
>Howdy,
>
>	I found out two weeks ago, that one has to switch on 
>soft-updates for ffs manually.
>
>I was wondring how many newbies know about this fact, how many of 
>us have done it, how we found out and if there are other tuning 
>facts we should care for.
>
>If the above is total gibberish to you, please do the following. 
>Type the command 'mount' on your shell and see if any of your 
>mounted filesystems has 'soft-updates' in the parantheses.
>	If this is not the case, and Your kernel has FFS (look in 
>/sys/<architacture>/conf/GENERIC), please read 'man tunefs' the 
>option to look for is '-n enable'.  Also look into 
>/usr/share/doc/smm (I guess that is 'System Manager Manual') under 
>05.fastfs is more information on the fast filesystem and soft updates.
>
>Why You should bother?  Have You ever tried to delete a large 
>directory structure, like /usr/ports ?  Have You ever wondered why 
>this takes half an hour or longer?  Well I did, but I thought I 
>had to live with it ... or change to another OS with a quicker 
>Filesystem.  Don't chang OS ... switch on softupdates.
>
>
>Have any of You found other tuning parameters that increased the 
>speed of their machine by an order of magnitude?  If so, please 
>tell me, or tell me where to read about it.
>
>
>Sincerely,
>
>	Robert S.
>
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