jgreco
Resident Grinch
- Joined
- May 29, 2011
- Messages
- 18,680
I was a bit bothered by the large number of available SATA ports and one or two free PCIe slots in the VM storage server here. With the boost from 64GB to 128GB of RAM, the 256GB M.2 Samsung XP941 with its AHCI interface for L2ARC was feeling a little dated anyways.
M.2 offers several interfaces to the host. Electrically, it can offer SATA or PCIe. The SATA is clearly a bit of a legacy hack in order to allow M.2 to be adopted more easily into first generation laptops. PCIe provides direct attachment from the flash controller to the host PCIe lanes, and can be either AHCI (essentially SATA protocol and commands run over the PCIe bus) or the newer, made-for-flash NVMe.
The real problem with any storage server is that sooner or later you want to add "more". And Addonics happened to have a very unusual card: it provides an M.2-to-PCIe interface, like several other adapters, but it ALSO provides power to two more M.2-to-SATA adapters on the same board. Three M.2 SSD's on a single board (two of which have to be plugged into SATA).
Front side of card, with two 500GB Samsung 850 EVO's. These two slots connect directly to the SATA ports directly adjacent.
Rear of card, with a 512GB Samsung 950 PRO.
We bought two cards right away but I held off on populating the second card because this is mostly for experimentation at this point.
I think what I'm going to try is creating a nice SSD datastore out of the 850 EVO's, and using the 950 for L2ARC. I may follow up to this thread as things develop.
2020/10: Additional note: The Addonics has become hard to find but Startech also sells the same exact card as PEXM2SAT32N1
M.2 offers several interfaces to the host. Electrically, it can offer SATA or PCIe. The SATA is clearly a bit of a legacy hack in order to allow M.2 to be adopted more easily into first generation laptops. PCIe provides direct attachment from the flash controller to the host PCIe lanes, and can be either AHCI (essentially SATA protocol and commands run over the PCIe bus) or the newer, made-for-flash NVMe.
The real problem with any storage server is that sooner or later you want to add "more". And Addonics happened to have a very unusual card: it provides an M.2-to-PCIe interface, like several other adapters, but it ALSO provides power to two more M.2-to-SATA adapters on the same board. Three M.2 SSD's on a single board (two of which have to be plugged into SATA).
Front side of card, with two 500GB Samsung 850 EVO's. These two slots connect directly to the SATA ports directly adjacent.
Rear of card, with a 512GB Samsung 950 PRO.
We bought two cards right away but I held off on populating the second card because this is mostly for experimentation at this point.
I think what I'm going to try is creating a nice SSD datastore out of the 850 EVO's, and using the 950 for L2ARC. I may follow up to this thread as things develop.
2020/10: Additional note: The Addonics has become hard to find but Startech also sells the same exact card as PEXM2SAT32N1
Last edited: