cmp(1) has a bottleneck, but where?

Tom Evans at
Mon Jan 16 12:05:55 UTC 2012

On Sun, Jan 15, 2012 at 11:32 PM, Dieter BSD <dieterbsd at> wrote:
> I recently read somewhere that zfs needs 5 GB memory for each 1 TB of disk.
> People that run zfs obviously don't care about using lots of memory.

You read incorrectly. To run zfs with dedup needs ~ 5GB of RAM per TB,
but this depends upon file size.

However, the majority of ZFS users do not use dedup. My pool is 18 TB
with 8 GB of RAM, of which ZFS can only access 4 GB.



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