Greetings,
I currently have a 3-drive RAIDZ1 pool of Crucial MX500 1TB SATA disks (CT1000MX500SSD1).
I also have another, M.2 Crucial MX500 1TB disk (CT1000MX500SSD4), not in the pool, of which i find no info on.
I intend to redo the pool from scratch and, as far as fdisk is concerned, these 4 are identical in all but model name.
The board is a Asus Prime X370-A and i’m sure there are speed differences between SATA and M.2, so the question is can i use the 4 together in a new pool? Can i use the M.2 as cache? Pros and cons? Suggestions?
@0x0 3.5” SATA, 2.5” SATA, and M.2 SATA are all the same speed (assuming they’re all the same version of the SATA specification). The MX500 is a SATA Drive, so it will have the same performance no matter which way you connect it.
For performance vdevs (cache, dedup, log, or special) to improve performance, they need to be noticeably faster than the capacity devices. For example, a SATA SSD makes a good performance vdev for a pool which gets its capacity from spinning disks. Since your pool is already SATA SSDs, a SATA SSD performance vdev won’t help. For a performance vdev to help you, it would have to be NVMe.
FYI, M.2 describes a form factor, and SATA is not. You can have a 2.5" SATA drive and an M.2 SATA drive, for example.
Though yes, M.2 SATA drives are generally faster.
