Sunday, January 4, 2015

Ceph Pi - oDroid Fail

I had a frustrating weekend.  I was really excited about making my oDroid U3 the controller for the Ceph cluster.  I was pumped.  The CPU runs like magic ( compile time of the kernel on board was comparable to an x64 ), and I keep being excited about its 2GB or RAM (but not the 100Mbs ethernet).

And yet...  I failed.  A lot.

It really seems to have to do with the kernel.  The oDroid comes with a 3.0 kernel.  I had to compile the RBD module.  And it was hell.  I failed to get the on-board compile to work.  When I failed - there was no way to get any feedback.  I would have it plugged into a screen and get no feedback whatsoever.   I finally got it working by doing a cross compile.  Technically there is a a 3.8 branch as well, but I did not manage to get it working (well, I really did not get to it in the end, so just keep reading).

So then I tried set it up as a mon / ceph-client.  And I failed.  And failed.  And failed.  In the end, I found this article which describes the features included in various versions of the kernel.  It turns out my 3.0 was just too old.  And even if I get 3.8 working, its likely going to be trouble as well, since it was missing a ton of features.   I tried every work around I could, but most posts really talked about 3.9 as being the earliest viable version.  And the oDroid does not seem to support it... at least with Ubuntu.

So I gave, up and set up my Intel NUC mini PC which is running x64 with Debian Jessie.

I have not given up on the oDroid yet, but it will be a couple of weeks before I forget my current level of frustration and give it another whirl.

This may be a blessing in disguise because I now have a gig port.