Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Boot on RAID Question

Tue Jan 22, 2013 10:28 pm

Hi Guys,

I am trying to get the Pi to boot off a RAID array (after the SD card has loaded the kernel - or course).

I have built RAID support into the kernel (not as a module).
I have created an array with metadata=0.90.
All devices contain partition type fd (linux raid auto-detect).
Edited cmdline.txt so it contains the line md=0,/dev/...,/dev/....,etc...

On reboot the kernel reports (at around 3 seconds) that 0 Devices Scanned 0 Found.

It seems that the USB devices are found just after this step. So, the array can't be found because of this.

Do you guys what needs to be done to the kernel to solve this?

As, I think it would make a massive difference to the Pi environment (especially in X) if it can throw data around at 55MB/s as opposed to 20MB/s. Don't you think ;)

Any ideas would be absolutely awesome. 8-)
Loving my peice of the Pi

Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Re: Boot on RAID Question

Wed Jan 23, 2013 9:09 pm

Great to know that I have gone from absolute Linux noob in two weeks to Uber-god. 8-)

I am now asking questions that no-one has the slightest clue on how to answer. :lol:
Loving my peice of the Pi

stubright
Posts: 109
Joined: Sat Dec 24, 2011 11:12 pm

Re: Boot on RAID Question

Wed Jan 23, 2013 10:56 pm

I'm no expert but what about adding
waitusb=5
to the end of the line in cmdline.txt (5 being the number of seconds to wait, it can be any number).
It makes the kernel wait for usb devices to be detected, if that is what the actual problem is.
I don't know if it works with all kernels as I've never had to use it (I've seen it used in TinyCore).
I hope it helps.
Stu

Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Re: Boot on RAID Question

Wed Jan 23, 2013 11:41 pm

Hi Stu, thanks for the reply.

I just tried your suggestion, but is didn't seem to make an effect on raspbian. It might just be a tiny core parameter. :?
Loving my peice of the Pi

stubright
Posts: 109
Joined: Sat Dec 24, 2011 11:12 pm

Re: Boot on RAID Question

Thu Jan 24, 2013 12:04 am

Hi again,
What about
rootdelay=5
You can probably guess what the 5 does (you could try a higher number if 5 isn't enough).
It's a generic kernel option, not the same as rootwait, it should delay booting long enough for your USBs to be ready to mount.
If that doesn't work I'll apologise now for wasting your time and crawl back under my rock.
Stu

Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Re: Boot on RAID Question

Thu Jan 24, 2013 12:26 am

Hi Stu, this actually looks more promising, I think we are now progressing further. Just have to copy some files and I'll let you know 8-)

Fingers crossed ;)
Loving my peice of the Pi

Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Re: Boot on RAID Question

Thu Jan 24, 2013 4:25 am

Stu, you are the man.

It worked. I am now booting straight into a RAID 0 array 8-)

I am just documenting the whole process now and will post how to go about it.
Loving my peice of the Pi

edmun
Posts: 39
Joined: Thu Jan 09, 2014 11:37 am

Re: Boot on RAID Question

Mon Oct 13, 2014 8:32 am

Lonewolff wrote:I am just documenting the whole process now and will post how to go about it
After almost 2 years - can I ask how is it going with this documentation?

Lonewolff
Posts: 144
Joined: Fri Dec 28, 2012 11:13 pm

Re: Boot on RAID Question

Mon Oct 13, 2014 8:48 pm

It is a masterpiece! 8-)
Loving my peice of the Pi

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