ZFS Recommendations for a new server

[Matthew Seaman]

On 05/30/14 16:11, Alejandro Imass wrote:
> The new server has a 2 x 1TB RE4 3ware 9650SE RAID and I have friends that
> tell me is actually better to use ZFS RAID instead of HW RAID1. Is this
> true? Why so?

I recently had a similar setup using an old 3ware RAID card, which we
upgraded to 4TB drives .... and then had to ditch the 3ware card and
replace it with a LSI HBA because the 3ware card didn't recognise
anything beyond the first 2TB or the drives.

Yes, you want to use ZFS RAID rather than putting ZFS onto a single
virtual drive presented by your RAID controller.  ZFS does all the
resilience and patrol read^W^Wzpool scrubbing and disk IO caching and
stuff using your system's main RAM and CPUs which are generally a lot
more capable than any RAID controller.  Plus ZFS does it better --
'punctured stripe' is not something that happens to ZFS for instance.

Even though 3ware does have a 'pass through' mode -- which is what
you'ld want with ZFS, the RAID controller still gets in the way to some
extent.  Just using a plain and simple HBA gives much better performance.

	Cheers,

	Matthew

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