[zfs-discuss] Dedup tables size in RAM ?

Aneurin Price aneurin.price at gmail.com
Mon Apr 30 10:08:32 EDT 2012

On 30 April 2012 14:23,  <swami at petaramesh.org> wrote:
> Thank you very much Aneurin,
> With this I now know it's worth purchasing another 4GB RAM in my case :-)
> Now Id' love to know how I can tell whether or not I have L2ARC, its size,
> and how to fine-tune things the best way.

You would have an L2ARC if you've added an extra device (preferably
SSD with fast random-read access) as a cache device. They're mostly
useful if your use case includes a lot of random reads that come
mostly from a set of data small enough to fit on the SSD - dedup is a
good case for using an L2ARC as the DDT fulfils these criteria.

> I'm not sure whether there is relevant doc for the Linux native ZFS for that
> ? Where should I set parameters, on what basis etc ?
That I don't know, as I've been fairly happy sticking to the defaults.

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