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To: Don Lewis <truckman@FreeBSD.org>
Subject: Re: access to hard drives is "blocked" by writes to a flash drive
In-reply-to: <201303040301.r2431Rjm008175@gw.catspoiler.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
References: <201303040301.r2431Rjm008175@gw.catspoiler.org>
Date: Mon, 04 Mar 2013 06:46:37 +0000
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Cc: deeptech71@gmail.com, freebsd-current@FreeBSD.org, peter@rulingia.com,
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In message <201303040301.r2431Rjm008175@gw.catspoiler.org>, Don Lewis writes:

>When using TCQ or NCQ, perhaps we should limit the number of outstanding
>writes per device to leave some slots open for reads.  We should
>probably also prioritize reads over writes unless we are under memory
>pressure.

Camera-grade flash seldom support either, they are strictly serial.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.