I believe the other frequent asked question is how to move the hashtable to a SSD. Currently there is no option for that. The reason for that is that we don’t know if it is worth the risk. At the moment hashstore with the hastable on disk is faster than piecestore + badger cache. We tested hashstore with hashtable on SSD and it would give us a small performance gain. At least for storj select with the high stream of short TTL data. Storj select could benefit from moving the hashtable to SSD. But there are 2 points to consider.
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Losing the badger cache is no big deal. The node can run with an empty badger cache and will slowly recreate it. Losing the hashtable is a ticket to get disqualified. Rebuilding the hashtable from scratch would require to read all LOG files (not implemented). Reading 20 TB of data will take a long time and in the meantime the node will have to stay offline to avoid audit failures. It might be possible to avoid the disqualification for a low number of nodes but even than we are still talking about weeks of downtime, getting suspended, reduction in used space caused by the repair system and so on. I would argue that this risk is not worth it. For bigger setups with multiple HDDs sharing the same SSD it gets unlikely to rescue all nodes in time.
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For a public node this extra performance might be meaningless. Storj select has to go down the throughput rabit hole. How much concurrent uploads can the customer push to a single node. Moving the hashtable to a SSD means a few more free IOPs on the HDD. For the public network this equasion is a bit different. A public node needs to optimize for a high upload success rate. There is a chance that moving the hashtable to a SSD has no measureable difference in upload success rate. In that case we would be talking about taking an unessesary risk. Please keep that in mind.
My plan is to wait how things develop in the storj select network. If the option to move the hashtable to a SSD gets implemented I might test it out on a node to see if there is a measureable difference in upload success rate. If there is almost no difference I will move the hashtable back to HDD. Why take an avoidable risk if there is no advantage to gain?