From mboxrd@z Thu Jan  1 00:00:00 1970
MIME-Version: 1.0
In-Reply-To: <93c5fcb996e7b29a732dfd6d0dbfe6bb@quanstro.net>
References: <dd6fe68a0906250913g66ab1442wb70b1ffbce0f6df7@mail.gmail.com>
	 <93c5fcb996e7b29a732dfd6d0dbfe6bb@quanstro.net>
Date: Thu, 25 Jun 2009 09:47:26 -0700
Message-ID: <dd6fe68a0906250947k67bfc11pfc84e17a6ee4dd1e@mail.gmail.com>
Subject: Re: [9fans] fossil/venti falling down?
From: Russ Cox <rsc@swtch.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Topicbox-Message-UUID: 0f145cde-ead5-11e9-9d60-3106f5b1d025

On Thu, Jun 25, 2009 at 9:24 AM, erik quanstrom<quanstro@quanstro.net> wrot=
e:
>> > does venti even keep scores on the bloom filter blocks and the icache?
>>
>> no, but those are soft data and can be reconstructed.
>
> being the paranoid type, i worry about this. =C2=A0does the
> rebuild rate on a large (say, 1tb) venti make this a
> practical strategy?

there's no question that a better strategy is to
use a 100% reliable underlying storage device.

if that's not available and one must cope with
disk failures some other way, it is very nice
that venti can use the sha1 checksums to check
the integrity of the core data and rebuild the rest.
this is what i do when a disk fails on the mit venti
backup server, which has about 5tb of data right now.
it takes about an hour to rebuild everything with
venti/buildindex.

russ