Semi-hack to ensure that Wisconsin nodes don't include their SSDs
in blockstore-related VGs. Right now, you have to decide globally and in advance, what disk types are going to be included in blockstore pools. Then you set the sitevar accordingly and then set the DB sysvol/nonsysvol/any node_type_features to reflect the amount of storage available on just drives of that type. This value is passed to clients via the otherwise unused PROTO field of the blockstore line (when CMD=SLICE and CLASS=local), so this change is backward compatible (OS images with older client code will ignore it and just give you blockstores including all the devices). So at Wisconsin, I set storage/local/disktype to "HDD-only" and tweak the node_type_attributes '?+disk_any' and '?+disk_nonsysvol' to not include the space for the 1 or 2 SSD drives in each machine. tmcd passes the PROTO=HDD-only value and the client sees that and does not include any SSD devices among the eligible devices from which to create the VG. The hope is that ultimately, we could get rid of the sitevar and use the PROTO field to select, per-blockstore, its type (only HDD, only SSD). But that will require additional per node (type) assign features differentiating the amount of each type available.