On Sun, Sep 09, 2018 at 03:32:47PM +0100, Wilson Jonathan wrote:
> Basically
> <-------- raid 0 --------->
> <- raid 1 -> <- raid 1 ->
> M1 M1 M1 M2 M2 M2
>
> If mdadm can't create the raid 10, with two three way mirrors
Well, according to the manpage:
Finally, the layout options for RAID10 are one of 'n', 'o' or 'f'
followed by a small number. The default is 'n2'. The supported
options are:
'n' signals 'near' copies. Multiple copies of one data block
are at similar offsets in different devices.
The number is the number of copies of each datablock. 2 is normal,
3 can be useful.
So in theory, raid10 with --layout=n3 and six drives should be it.
Three copies of each data block in a single RAID, as requested.
In practise it seems few people use this option. When I tried it,
with six 100M-loopdevs just for testing it, the kernel oopsed out.
(unable to handle kernel NULL pointer dereference in r10buf_pool_alloc)
Regards
Andreas Klauer
