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Re: [zfs-discuss] Tool to figure out optimum ZFS recordsize for a Mail s

Subject: Re: [zfs-discuss] Tool to figure out optimum ZFS recordsize for a Mail server Maildir tree?
From: Roch Bourbonnais
Date: Thu, 27 Nov 2008 17:25:45 +0100
Le 22 oct. 08 à 21:02, Bill Sommerfeld a écrit :

> On Wed, 2008-10-22 at 09:46 -0700, Mika Borner wrote:
>> If I turn zfs compression on, does the recordsize influence the
>> compressratio in anyway?
>
> zfs conceptually chops the data into recordsize chunks, then  
> compresses
> each chunk independently, allocating on disk only the space needed to
> store each compressed block.
>
> On average, I'd expect to get a better compression ratio with a larger
> block size since typical compression algorithms will have more  
> chance to
> find redundancy in a larger block of text.
>

With gzip yes, but with default compression, I believe lzjb is looking  
for short 'repeating byte pattern'.
It should not depend much on recordsize.

-r


> as always your mileage may vary.
>
>                                               - Bill
>
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