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Date: Wed, 05 Jul 2006 08:06:05 -0400
From: Bill Davidsen <davidsen@tmr.com>
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To: Avi Kivity <avi@argo.co.il>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Arjan van de Ven <arjan@infradead.org>, Tomasz Torcz <zdzichu@irc.pl>,
       Helge Hafting <helgehaf@aitel.hist.no>,
       Thomas Glanzmann <sithglan@stud.uni-erlangen.de>,
       "Theodore Ts'o" <tytso@mit.edu>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: ext4 features (checksums)
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Avi Kivity wrote:
> Neil Brown wrote:
>>
>> To my mind, the only thing you should put between the filesystem and
>> the raw devices is RAID (real-raid - not raid0 or linear).
>>
> I believe that implementing RAID in the filesystem has many benefits too:
> - multiple RAID levels: store metadata in triple-mirror RAID 1, random 
> write intensive data in RAID 1, bulk data in RAID 5/6
> - improved write throughput - since stripes can be variable size, any 
> large enough write fills a whole stripe
> 
I rather like the idea of allowing metadata to be on another device in 
general, or at least the inodes. That way a very small chunk size can be 
used for the inodes, to spread head motion, while a larger chunk size is 
appropriate for data in some cases.

Larger max block sizes would be useful as well. Feel free to discuss the 
actual value of "larger."

-- 
Bill Davidsen <davidsen@tmr.com>
   Obscure bug of 2004: BASH BUFFER OVERFLOW - if bash is being run by a
normal user and is setuid root, with the "vi" line edit mode selected,
and the character set is "big5," an off-by-one errors occurs during
wildcard (glob) expansion.