On 9/16/12 10:40 AM, "Richard Elling" <richard.ell...@gmail.com> wrote:

>With a zvol of 8K blocksize, 4K sector disks, and raidz you will get 12K
>plus parity) written for every block, regardless of how many disks are in
>the set.
>There will also be some metadata overhead, but I don't know of a metadata
>sizing formula for the general case.
>So the bad news is, 4K sector disks with small blocksize zvols tend to
>have space utilization more like mirroring. The good news is that
>is also more like mirroring.
> -- richard

Ok, that makes sense. And since there's no way to change the blocksize of
a zvol after creation (AFAIK) I can either live with the size, find 3TB
drives with 512byte sectors (I think Seagate Constellations would work)
and do yet another send/receive, or create a new zvol with a larger
blocksize and copy the files from one zvol to the other. (Leaning toward
option 3 because the files are mostly largish graphics files and the like.)

Thanks for the help!
Dave Pooser
Manager of Information Services
Alford Media  http://www.alfordmedia.com

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