I might be well wide of the mark, but I am wondering if @HankCao is trying to do some kind of 'omics analysis. I suspect this because of things like running large numbers of GLMs and the variable names exp and pheno look like expression and phenotype.
If this is the case, then it might be appropriate to wait for the forthcoming work on DataSHIELD 'omics functions? I have seen that the use of the limma package really speeds up running '000s of glms…
Apologies if I have completely misunderstood
Tom