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Date:      Thu, 10 May 2001 12:54:06 +0930
From:      Greg Lehey <grog@lemis.com>
To:        Dan Phoenix <dphoenix@bravenet.com>
Cc:        FreeBSD Questions <questions@FreeBSD.org>
Subject:   Re: vinum on 2 ide drives?
Message-ID:  <20010510125406.I56501@wantadilla.lemis.com>
In-Reply-To: <Pine.BSO.4.21.0105091950450.7249-100000@gandalf.bravenet.com>; from dphoenix@bravenet.com on Wed, May 09, 2001 at 07:51:05PM -0700
References:  <Pine.BSO.4.21.0105091950450.7249-100000@gandalf.bravenet.com>

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On Wednesday,  9 May 2001 at 19:51:05 -0700, Dan Phoenix wrote:
>
>
> These 2 are from running it on each on the ide drives without vinum.
>
> [root@gorbag /mnt1]# dd if=/dev/zero of=bigfile bs=16384k count=1000
> 1000+0 records in
> 1000+0 records out
> 16777216000 bytes transferred in 799.865832 secs (20975038 bytes/sec)
> [root@gorbag /mnt2]# dd if=/dev/zero of=bigfile bs=16384k count=1000
> 1000+0 records in
> 1000+0 records out
> 16777216000 bytes transferred in 796.395885 secs (21066427 bytes/sec)
> [root@gorbag /mnt2]#
>
> This is from running it on both drives striped with vinum.
>
> [root@gorbag /backup]# dd if=/dev/zero of=bigfile bs=16384k count=1000
> 1000+0 records in
> 1000+0 records out
> 16777216000 bytes transferred in 1365.405607 secs (12287350 bytes/sec)
> [root@gorbag /backup]#
>
> seems to be quite abit slower..

Indeed.  That's puzzling.

> now i was running systat -vm 1 while writing to the striped vinum
> drive and did see both of them getting hit equally. IN this case
> prob at around 99% IO on both of them half the time.
>
> [root@gorbag dphoenix]# cat /etc/vinum.conf
> drive ibm1 device /dev/ad1s1e
> drive ibm2 device /dev/ad2s1e
> volume stripe
>   plex org striped 512s
>     sd length 58643m drive ibm1
>     sd length 58643m drive ibm2
> [root@gorbag dphoenix]#

You shouldn't be using power-of-2 stripes.  But that's not what's
causing your problem.s

> ad1: 58644MB <IBM-DTLA-307060> [119150/16/63] at ata0-slave UDMA33
> ad2: 58644MB <IBM-DTLA-307060> [119150/16/63] at ata1-master UDMA33

Nice drives.  They should be much faster than that on dd, but you were
going via the file system.

> Any suggestions to get some speed here? Or should i just go back to
> single ide drives split up again?

I'd like to understand what's going on here first.  This isn't typical
behaviour.  Since you seem to not have anything useful on the drives,
could you repeat with rawio (/usr/ports/benchmarks/rawio)?  We can
also take this offline.

Greg
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