[ceph-users] Advice on SSD choices for WAL/DB?

Hello, We are planning to perform a small upgrade to our cluster and slowly start adding 12TB SATA HDD drives. We need to accommodate for additional SSD WAL/DB requirements as well. Currently we are considering the following: HDD Drives - Seagate EXOS 12TB SSD Drives for WAL/DB - Intel D3 S4510 960GB or Intel D3 S4610 960GB Our cluster isn't hosting any IO intensive DBs nor IO hungry VMs such as Exchange, MSSQL, etc. From the documentation that I've read the recommended size for DB is between 1% and 4% of the size of the osd. Would 2% figure be sufficient enough (so around 240GB DB size for each 12TB osd?) Also, from your experience, which is a better model for the SSD DB/WAL? Would Intel S4510 be sufficient enough for our purpose or would the S4610 be a much better choice? Are there any other cost effective performance to consider instead of the above models? The same question to the HDD. Any other drives we should consider instead of the Seagate EXOS series? Thanks for you help and suggestions. Andrei