Adding M.2 capability….

[Camnomis]

I have a Dell T340 with a H310 HBA flashed into IT mode.

 

Connected to this is have several 8TB SAS drives, and I’m led to believe the H310 uses a LSI SAS 2008 chip, which is SAS2, however as I’m using HDD not SSD this is not a problem as there should be no way to hit the throughout bottle neck.

 

I want to add some SSD’s as a cache pool, and have two options 2.5” or M.2.

If I use a 2.5” SATA drive I should have no problem connecting it via the H310, it’s only SAS SSDs that it might struggle with?

 

If I go the M.2 route I’d have to get a PCIE SSD adapter like this https://www.ebuyer.com/816612-startech-com-m-2-pcie-ssd-adapter-x4-pcie-3-0-nvme-m-2-pex4m2e1 would this give me a performance increase over the SATA connection given the H310 is connected to PCIE (although 2.0) anyway?

 

Edited February 1, 2022 by Camnomis

[Hoopster]

15 minutes ago, Camnomis said:

If I use a 2.5” SATA drive I should have no problem connecting it via the H310

Sure you can connect SATA 2.5" SSDs but the H310 is a PCIe 2.0 card so there is limited bandwidth.  Depending on how many other disks are connected to the HBA, you likely will not get the full speed the SSD can provide.  Another issue is that the card does not support deterministic TRIM on SSDs so performance will degrade over time.

 

PCIe adapter you linked is PCIe 3.0 so double the bandwidth of PCIe 2.0 (assuming your motherboard/chipset support PCIE3.0)

Edited February 1, 2022 by Hoopster

[Camnomis]

49 minutes ago, Hoopster said:

Sure you can connect SATA 2.5" SSDs but the H310 is a PCIe 2.0 card so there is limited bandwidth.  Depending on how many other disks are connected to the HBA, you likely will not get the full speed the SSD can provide.  Another issue is that the card does not support deterministic TRIM on SSDs so performance will degrade over time.

 

PCIe adapter you linked is PCIe 3.0 so double the bandwidth of PCIe 2.0 (assuming your motherboard/chipset support PCIE3.0)

Thanks, will need to double check the motherboard but I think I’m ok.

 

So next question, if I go down the M.2 route do I then need to consider the SATA vs NVMe options? If I’m future proofing the system should I be looking at an adapter that is NVMe capable rather than SATA?

 

Most of the dual M.2 PCIE cards (I’ll need two drives to enable a level of protection for the cache pool) have a M Key (NVMe) and a B Key (SATA) which is self explanatory, but are the M Key slots compatible with SATA drives? As I’m guessing mixing a NVMe and a SATA SSD would not be very efficient would I need two single M.2 PCIE (either B or M) cards as the cost of a Dual M Key card would be way over budget?

Edited February 1, 2022 by Camnomis

[Hoopster]

1 hour ago, Camnomis said:

So next question, if I go down the M.2 route do I then need to consider the SATA vs NVMe options? If I’m future proofing the system should I be looking at an adapter that is NVMe capable rather than SATA?

Again, depending on the motherboard, SATA M.2 can disable a regular SATA port on the motherboard depending on how it is engineered and the capabilities of the chipset.  That is the way it is with my motherboard.  SATA M.2 means I lose a SATA port.  I have a PCIe M.2 installed which does not disable the SATA port.

 

I always look for PCIe SSDs for the M.2 slots on the MB. 

 

I doubt installing a SATA M.2 on a PCIe adpater would have any affect on SATA ports as the interface is PCIe for the adapter card and only needs the number of PCIe lanes the card requires.

[Camnomis]

10 hours ago, Hoopster said:

Again, depending on the motherboard, SATA M.2 can disable a regular SATA port on the motherboard depending on how it is engineered and the capabilities of the chipset.  That is the way it is with my motherboard.  SATA M.2 means I lose a SATA port.  I have a PCIe M.2 installed which does not disable the SATA port.

 

I always look for PCIe SSDs for the M.2 slots on the MB. 

 

I doubt installing a SATA M.2 on a PCIe adpater would have any affect on SATA ports as the interface is PCIe for the adapter card and only needs the number of PCIe lanes the card requires.

 

Awesome, thanks for your help so far (if there is a way to send virtual beer tokens let me know!)

 

Hopefully this is the last question....

 

At the moment I have 5 x HDD and 1 x SSD connected to the HBA, which is a x8 PCIe card, I am not sure which slot on the motherboard it is connected to without opening the case and checking but the tech specs say I should have:

● 1 x 8 PCIe Gen3 (x16 connector) FH/HL
● 1 x 8 PCIe Gen3 (x8 connector) FH/HL

● 1 x 4 PCIe Gen3 (x8 connector) FH/HL
● 1 x 1 PCIe Gen3 (x1 connector) FH/HL

If I were to add 2 x x4 PCIe to M.2 adapters (a x4 should fit in an x8 slot) I will not exceed the max 16 lanes the CPU can handle, and couple with 2 x Samsung 970 EVO Plus it should theoretically work, I could play it safer with a Dual M.2 PCIe SSD Adapter Card in a x8 or x16 slot which can take two SSD's but there is quite a cost uplift for this approach

[JorgeB]

Fist two slots use CPU lanes, last two go though the PCH, so they share the DMI with onboard SATA, NIC, etc.

[Camnomis]

10 minutes ago, JorgeB said:

Fist two slots use CPU lanes, last two go though the PCH, so they share the DMI with onboard SATA, NIC, etc.

 

I read up a little on that, and the CPU lanes are only really important for a GPU (which I am not using in my box) and storage should be fine on PCH?

 

I only have one SATA drive and thats connected to the backplate and the HBA and a single NIC with two ports

Edited February 2, 2022 by Camnomis

[JorgeB]

CPU lanes are better for everything when available, since they are not shared with anything else and have lower latency, but depending on the total devices going thought he DMI and if they are used concurrently it might not make a big difference, DMI in this case is PCIe 3.0 x4.