[Linux-cluster] gnbd/clvm and device mapper : 256 devices limitation ?

[Sylvain COUTANT]

Hello the list,

I was wondering if it were at all possible to have more than 256 block devices shared in a cluster.

I'd like to export gnbd devices (10-15) with volume groups on top. There would be many lvs (up to 256) in each vg.

Question is : how the device mapper will handle this on each cluster member ?

I ran a basic test by creating more than 256 lvs in a single vg and device mapper did create devices twice with the same major/minor (wrapping after minor 255).

Basically, that would mean I won't be able to share more than 256 lvs amongst the entire architecture. This limitation is far too low for me. I'd prefer hear about 10000+ ;-)

I know this question is not directly related to the cluster project (except the clvm part), but since I have chances to find here some people with knowledge about large architectures, I try it anyway ...


Thanks in advance for any tip.


--
Sylvain COUTANT

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