Re: Recovery of failed RAID 6 and LVM

[David Brown <david@westcontrol.com>]

On 29/09/2011 01:49, NeilBrown wrote:
> On Wed, 28 Sep 2011 11:12:08 -0500 Stan Hoeppner<stan@hardwarefreak.com>
> wrote:
>
>> On 9/28/2011 2:10 AM, Marcin M. Jessa wrote:
>>> On 9/28/11 4:50 AM, Stan Hoeppner wrote:
>>>
>>>> Reading the thread, and the many like it over the past months/years, may
>>>> yield a clue as to why you wish to move on to something other than Linux
>>>> RAID...
>>>
>>> :) I will give it another chance.
>>> In case of failure FreeBSD and ZFS would be another option.
>>
>> I was responding to Neil's exhaustion with mdadm.  I was speculating
>> that help threads such as yours may be a contributing factor,
>> requesting/requiring Neil to become Superman many times per month to try
>> to save some OP's bacon.
>>
>
> No, I don't really think they are a factor - though thanks for thinking
> about it.
>
> Obviously not all "help threads" end with a good result but quite a few do
> and one has to take the rough with the smooth.
> And each help thread is a potential learning experience.  If I see patterns
> of failure recurring it will guide and motivate me to improve md or mdadm to
> make that failure mode less likely.
>
> I think it is simply that it isn't new any more.  I first started
> contributing to md early in 2000, and 11 years is a long time.  Not as long
> as Mr Torvalds has works on Linux of course, but Linux is a lot bigger than
> md so there is more room to be interested.
> There have been many highlights over that time, but the ones that stick in my
> memory is when others have contributed in significant ways.  I really value
> that, whether it is code, or review or documentation, or making a wiki or
> answering mailing lists questions before I do, or even putting extra time in
> to reproduce a bug so we can drill down to the cause.
>
> I figure that appearing competent capable and in control isn't going to
> attract new blood - new blood wants wide open frontiers with lots of
> opportunity (I started in md when it was essentially unmaintained - I know
> the attraction).  So I just want to say that there is certainly room and
> opportunity over here.
>
> I'm not about to drop md, but I would love an apprentice or two (or 3 or 4)
> and would aim to provide the same mix of independence and oversight as Linus
> does.
>
> NeilBrown

One challenge for getting apprentices in this particular area is the 
hardware costs.  For someone to be able to really help you out in 
development and serious testing of md, they are going to need access to 
a machine with plenty of disks, preferably with hotplug bays and with a 
mix of hdds and ssds.  That's going to out of reach for many potential 
assistants - it is hard enough finding someone with the required talent, 
interest and time to spend on md/mdadm.  Finding people with money - 
especially people using md raid professionally - should be a lot easier. 
  So if there is anyone out there who is willing and able to contribute 
seriously to md/mdadm, but is hindered by lack of hardware, then I for 
one would be willing to contribute to a fund to help out.