Description of problem: the current implementation of the multiple devices subsystem limits md devices to 12 drives, including spares. the man page for raidtab indicates that a patch to extend this to 256 drives exists. please consider applying this patch to future kernels.
"12" is a bogus limit indeed; the real limit is 27 and we're evaluating if a fix for that is enough to warrant a raidtools erratum. Above 27 is not possible without changing the on-disk format and as a result is rather more invasive....
27 would be helpful for us, especially if it is easy to do. Sounds like going past 27 is something for 8.0.
I haven't tried lately, but is this better in recent kernels?
current limit still is 27 ;( there is a on-disk layout change required for going above that, and THAT needs upstream buy-in and such
sorry for not being clear. I haven't tested lately if the limit of 12 has been removed so the 27 limit can be reached. I agree that exceeding the 27 limit is an upstream issue and not an easy question.
> 12 should work in current kernels.