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On Sun, Jun 6, 2010 at 3:26 AM, Roy Sigurd Karlsbakk <roy@xxxxxxxxxxxxx> wrote:
> ----- "Brandon High" <bhigh@xxxxxxxxxx> skrev:
>> Decreasing the block size increases the size of the dedup table
>> (DDT).
>> Every entry in the DDT uses somewhere around 250-270 bytes.
>
> Are you sure it's that high? I was told it's ~150 per block, or ~1,2GB per
> terabytes of storage with only 128k blocks
No, that's the number that stuck in my head though.
Even if the DDT entry is smaller, the point I was making doesn't
change. A smaller record size will increase dedup performance at the
cost of a larger DDT. Once the DDT is too large to fit in the ARC,
performance tanks.
-B
--
Brandon High : bhigh@xxxxxxxxxx
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