up your block size bro 💪 get them plates stacking 128KB+ a write and watch your throughput gains max out 🏋️ all the ladies will be like🙋♀️. Especially if you get those reps sequentially it's like hitting the juice 💉 for your transfer speeds.
For a full 32GB at the max sustained speed(275MB/s), 32ish hours to transfer a full amount, 36 if you assume 250MB/s the whole run. Probably optimistic. CPU overhead could slow that down in a rebuild. That said in a RAID5 of 5 disks, that is a transfer speed of about 1GB/s if you assume not getting close to the max transfer rate. For a small business or home NAS that would be plenty unless you are running greater than 10GiBit ethernet.