help creating new gmirror > 2TB

[Mikhail Goriachev]

On 29/08/2017 17:12, William Dudley wrote:
> Hi,
> 
> I want to create a simple mirror > 2TB on a FreeBSD 10.3 system.
> 
> I have 2 identical 4TB disks.
> 
> The examples in freebsd handbook "geom-mirror" pages show creation of a 2TB
> mirror using
> MBR partitioning, and that has an upper limit of 2TB.
> 
> Some documentation says not to use GPT partitioning with gmirror because
> both store their information in the last sector on the disk.
> 
> I'm not expert enough to be able to solve this myself.
> 
> How do I create a gmirror of 4TB size?
> 
> I want to partition it into 4 slices after I create it, but think I can use
> gpart to do that.
> 
> Note: I'm not interested in using zfs unless there's no way to do this with
> gmirror.
> I read too many zfs failure stories on this mailing list to be comfortable
> with zfs.
> 
> Thanks in advance,
> Bill Dudley


Hi Bill,

Great articles that helped me a lot back awhile:

http://www.wonkity.com/~wblock/docs/html/disksetup.html
http://www.wonkity.com/~wblock/docs/html/gmirror.html

In regard with disk thrashing, just mirror one essential partition. IMO
thrashing isn't that bad if it happens once or twice a year... but it
takes a long time and the disks go nuts. GPT is the way to go in your
situation.


Cheers,
Mikhail.

-- 
Mikhail Goriachev
Webanoide