I’d like to accentuate that creating wider vdev does not automatically mean you get better space efficiency. It is true only if you have blocks (and files) big enough for each device in the vdev to get at least 8KB or better 32KB after compression. So in case of 8-wide RAIDZ1 you’d better have block sizes after compression of at least 256KB. Just last week I’ve had couple cases when user put ZVOL with 32KB volblocksize onto 9-wide RAIDZ2, as result getting both worst possible IOPS, highest possible CPU overhead and space efficiency of only 66%. He could get the same space efficiency but at 3x IOPS would he use 3x 3-wide RAIDZ1, or 80% efficiency at 2x IOPS with 2x 5-wide RAIDZ1. While on NVMe devices IOPS are cheaper, per-IOPS CPU overhead may just explode, so it should better be for a good reason.