Read intensive SSDs are a bit of a marketing term. All SSDs will easily handle reads, but the name is referring to the lower write endurance. They will, however, provide the best cost per GB. These SSDs will often only have a write endurance of around 0.3-1 over a 5 year period drive writes per day (DWPD). That is to say you should be able to write 400 GB a day to a 400 GB SSD and expect it to still be working in 5 years' time. If you write 800 GB a day to it, it will only be guaranteed to last 2.5 years. In general, for most Ceph workloads, these ranges of SSDs are normally deemed to not have enough write endurance.