Re: How to do a software based RAID 1+0?

["Constantine A. Murenin" <mureninc@xxxxxxxxx>]

On 26 February 2013 12:14, Samuel J. Greear <sjg@evilcode.net> wrote:
> On Tue, Feb 26, 2013 at 1:06 PM, Joel Nilsson <joel@alikzus.se> wrote:
>> Hi,
>>
>> if I want to do soft RAID10 is vinum(8) the way to go?
>>
>> The main purpose is to crank up the I/O rate without loosing too much reliability.
>>
>> It is intended for my personal/private file server at home, so a temporary loss of availability is not an issue (for now, it may change).
>>
>> Regards,
>> Joel
>
> There are various options for software raid in DragonFly but a
> hardware raid controller is generally considered the most reliable
> option.
>
> Typically though in DragonFly you would hammer mirror-stream between
> disks for redundancy and utilize swapcache to acheive your throughput
> needs.
>
> Sam

So, `hammer mirror-stream` is the recommended way for redundancy in
place of software RAID, and where hardware RAID is not available?

Would such a setup support reliable booting from either volume?

Provided you have lots of RAM (e.g. 8GB or 16GB), is there a way to
ensure that you aren't going to be doing any actual IO on the source
volume when performing the mirroring?

If you're dealing with regular platter-based HDDs, would you
nonetheless configure the second HDD (which is the target of the
`hammer mirror-stream`) as swapcache?  Wouldn't it potentially make
the performance much worse?

C.