On 2011-06-24 01.39, Matthew Dempsky wrote:
> What should be done about ccd(4) and raid(4)? They both seem
> superseded in functionality by softraid(4), which also has much more
> developer interest and active development.
Never used ccd(4) so can't comment on that, but RAIDframe (raid(4)) has
a lot of functionality that is not yet implemented in softraid(4).
It has (for good reason given that softraid(4) is in the works) received
little developer attention and has a few bugs and other shortcomings.
I've tried in the past to address those I've run up against, but I know
there are probably more problems with it than is worth fixing (in
particular I've had problems with very large disks and raid sets) so I
have high hopes for softraid(4) in the future.
> Are there any users still using ccd(4) and/or raid(4) and unable to
> upgrade to softraid(4)? Will anyone be up a creek if ccd(4)/raid(4)
> were removed?
I for one will be up the worst of creeks if raid(4) was removed, that
would force me to stay on 4.9 until softraid(4) have evolved enough
(which I have no doubt will happen eventually), so please please don't
remove raid(4) just yet. :-)
My wish list for softraid(4) to enable me to say goodbye to RAIDframe
is something like this (not exhaustive and in no particular order):
- More complete RAID support overall, including
- ability to tune stripe sizes
- parity initialization / rebuilding, preferrably with background
mode
- Hot spare support
- Better handling of stripe (disk) failures
- Better handling of recovery from failed stripes (ability to hot
plug a replacement disk and rebuild on the spot for example)
- Full stripe writes for perfomance
- Usable status reporting
- Stripe on stripe (on stripe ...) support to be able to build
RAID 0+1 and RAID50 sets, as well as crypto on raid (this may
work now, haven't tried lately)
- RAID6 support (way way back in priority though)
- Bootable/rootable raid sets (I know this is close now)
- More consistent sd<n> unit allocation (perhaps this is achievable
with DUID, I haven't had time to explore that yet)
- Probably other small features as well, that I'll probably think
of the moment I've sent this mail off...
Regards,
/Benny
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