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Date:      Mon, 10 Nov 2003 11:32:42 -0500
From:      "Boring, Andrew" <Andrew.Boring@millerzell.com>
To:        <freebsd-questions@freebsd.org>
Subject:   Disk block size tuning - multiple questions
Message-ID:  <E7913F191C480F458C2B9B40F493FA3EB1D6@WS-EXCHANGE2003.corp.millerzell.com>

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Greetings!

First question:
I am configuring a server to hold source trees for 4.8/4.9 and maybe =
-current for production and experimental upgrades on my several FreeBSD =
servers. Currently, I only keep the -release sources for maintaining =
patchlevels on the individual boxes themselves. The last time I started =
adding the -current source tree on a non-production server, I ran out of =
inodes before actually completing the CVS sync. What newfs =
blocksize/fragment size and inode density is optimal for 10 to 16 GB =
partition containing just source trees? The default stripe size on the =
RAID controller is set to 128k for mirrored drives.

Hardware: Compaq ProLiant DL360, dual 18GB (mirrored) drives, with =
Compaq 5i SmartArray controller. FreeBSD 5.1

Next question:
Are there optimal newfs block/fragment/inode options for a quad-disk, =
1+0 RAID for a mail server running Postfix? Specifically, the queue =
directory and the home (Maildir) directories are what I'll need to =
optimize. I think the queue directory will be heavy read/write, whereas =
I imagine that the Maildir directories (kept on a different partition) =
will be more write-intensive over-all. The queue directory will reside =
on a (approximately) 1 GB /var partition, and the Maildirs will be on a =
roughly 27 GB /home partition (no other user files on /home). The =
default stripe size on the RAID controller is set to 128k for mirrored =
drives. I was looking at the tuning(7) recommendations of something like =
block size 8192 and frag size 1024 for the queue and Maildir =
directories. SInce Maildir will have to accomodate occasional large =
files with attachments, this seems like it might be a happy medium. I =
don't have a specific usage pattern developed on the number of/size of =
email files and attachments, so I am planning on a vague, nebulous =
"average email use".

Hardware: SGI 1200, quad 18GB (RAID 1+0) drives, Compaq 4200 SmartArray =
controller, FreeBSD 4.9

Another question:
I've been doing a lot of reading on filesystem/RAID levels for database =
use (I'm not a DB guy). I don't have a server ready for this yet, but i =
would like some generic recommendations on filesystem setup. I've read =
that mirrored stripes (0+1 or 1+0) is better overall than RAID 5. Any =
other tuning tips, such as block size, inode, async/sync/softupdates, =
etc for a partition to hold an SQL database (such as MySQL or Postgres, =
etc)? The tuning(7) man page seems to indicate a default block size =
(16k) but fewer inodes for databases.

Hardware: SGI 1200, quad 18GB (RAID 1+0) drives, Compaq 4200 SmartArray =
controller, FreeBSD 4.9

Last question:
With a good battery-backed caching controller (such as the Compaq =
SmartArray cards), is SoftUpdates of any use? My understanding is that =
SoftUpdates does in software the same sort of caching that RAID =
controllers would do. Am I correct or way off base? Should I mount all =
drives synchronous without SoftUpdates, or asynchronous with =
SoftUpdates, or what is the recommended choice when using real =
server-class SCSI RAID controllers? I am more concerned overall with =
higher-availability than higher-performance.

Thanks in advance!
(please Cc: me on all responses for this thread; I'm not subscribed)

--
Andrew Boring
Miller Zell Desktop Services
<andrew.boring@millerzell.com>=20

"Microsoft DNS service terminates abnormally when it receives a
response to a dns query that was never made. Fix information: run your
DNS service on a different platform." -- bugtraq
http://www.securityfocus.com/archive/1/6212



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