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Date:      Mon, 19 Nov 2001 20:58:45 -0600 (CST)
From:      Chris Dillon <cdillon@wolves.k12.mo.us>
To:        Christopher Farley <chris@northernbrewer.com>
Cc:        Greg Lehey <grog@FreeBSD.ORG>, <questions@FreeBSD.ORG>
Subject:   Re: Slow restores on a DLT4000
Message-ID:  <Pine.BSF.4.32.0111192049250.13508-100000@mail.wolves.k12.mo.us>
In-Reply-To: <20011119200058.B92015@northernbrewer.com>

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On Mon, 19 Nov 2001, Christopher Farley wrote:

> Oh yeah, soft updates are not enabled, but I plan to fix that
> soon. And a `restore -N` (with no disk writes -- don't know about
> metadata updates) takes just as long as a regular restore.

It sounds like you aren't using a large enough block size.  The
documentation for your drive should mention a minimal block size to
use to be able to stream data constantly.  I think it is at least 32KB
for most DLT drives.  IIRC, I'm using a 64KB or 128KB block size on my
DLT1 at work (albeit with Windows NT).

Running systat -vmstat and watching sa0 in the "Disks" section will
tell you what block size is actually being used.

--
 Chris Dillon - cdillon@wolves.k12.mo.us - cdillon@inter-linc.net
 FreeBSD: The fastest and most stable server OS on the planet
 - Available for IA32 (Intel x86) and Alpha architectures
 - IA64, PowerPC, UltraSPARC, and ARM architectures under development
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