linux-kernel - Re: document ext3 requirements

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <129621.1231077195@turing-police.cc.vt.edu>
Date:	Sun, 04 Jan 2009 08:53:15 -0500
From:	Valdis.Kletnieks@...edu
To:	"Alexander E. Patrakov" <patrakov@...il.com>
Cc:	Pavel Machek <pavel@...e.cz>,
	kernel list <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...l.org>, tytso@....edu,
	mtk.manpages@...il.com, rdunlap@...otime.net,
	linux-doc@...r.kernel.org, Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: document ext3 requirements

On Sun, 04 Jan 2009 18:35:41 +0500, "Alexander E. Patrakov" said:

> Ext3 means either hardware that supports barriers (not sure how to 
> check, and anyway I have to use encryption on the work laptop due to the 
> corporate policy) or disabling write cache (but, as Alan Cox said, this 
> shortens the lifespan of the disk).

False dichotomy.  This isn't an "either/or", as there's a *third* case:

"understand the issues and risks involved if you have a write cache and
no barrier support, and learn to deal with it".

As you point out, if it's a laptop with a battery, the risk may be *very* low.
Let's say there's a 1 in 10,000 chance that you'll trash a file system and
need to restore from backups.

That may be totally acceptable if you've already estimated a 1 in 500 chance
of the whole damned laptop going walkies while you're not looking, and then
you *still* need to be able to restore from backups onto a replacement machine.

Yes, for some systems, the whole barriers/write cache thing is in fact very
important.  But for others, data loss due to spilled coffee is a bigger worry...

Content of type "application/pgp-signature" skipped