Guidelines for using CombineGVCFs
In the documentation for CombineGVCFs it says:
CombineGVCFs is meant to be used for hierarchical merging of gVCFs that will eventually be input into GenotypeGVCFs. One would use this tool when needing to genotype too large a number of individual gVCFs; instead of passing them all in to GenotypeGVCFs, one would first use CombineGVCFs on smaller batches of samples and then pass these combined gVCFs to GenotypeGVCFs.
Do you have any guidelines for this? I am trying to use genotypeGVCFS on 12 gVCF files and it doesn't work, so can you advise how I should I "pre-merge" them? Two batches of 6? Three batches of 3?