M.2 PCI Adapter

[Vodka2014 8]

Hi All,

 

So I have been looking and I see that if the M.2 is on the Motherboard it can only be used and Read OR Read-Write Cache and not as a Storage Device to use like a Normal SSD or HDD.

 

If i get a PCI-E Adapter with 2 / 4 M.2's on them will this work for 918+ Or what is recommended OR if somehow I can use the M.2 Other then Cache. 

 

Thanks in advanced. 

[flyride 515]

M.2 is a multi purpose interface, and its implementation is dependent upon the motherboard or host card. Some or all of the following may be true:

• Most people think of M.2 as an interface to a NVMe SSD, but in reality the NVMe card is a PCIe device.  In that respect, it's a PCIe slot in a different form.
• A NVMe SSD is simply a PCIe device that fits into the M.2 slot form factor.
• The M.2 slot can also be mapped to a M.2 SATA SSD and internally connected over the same edge connector to a SATA HBA.

Assuming it is supported by the motherboard or card, an M.2 SATA SSD should work fine with DSM as it is seen as a SATA device.

 

A PCIe adapter with multiple M.2 slots is simply a PCIe switch or bifurcator.  For what it's worth, you can buy M.2 to PCIe adapters as well.

 

You already know that a M.2 NVMe SSD cannot be natively used by DSM as regular disk, just as cache (with patch).  Your best functional option to use NVMe with DSM is to install DSM within a hypervisor (ESXi), which can then virtualize and syndicate the NVMe storage to DSM as a VMDK (virtual disk image) or RDM (raw device mapping).  RDM is preferable as it performs better, gives you 100% of the space and the device can be directly attached to a virtual SATA controller so it appears as SATA to DSM.

Edited January 14 by flyride

[Vodka2014 8]

Thanks @flyride

 

Question. Since I have the system up and running now I take it that i cannot install ESXI on Docker and then use the M.2 as RDM i need to start over correct ?

 

If i cannot do much with the M.2 on the MB then i might get 2 of them on an PCI Card and make it RAID-1 for storage use.

 

Thanks

[flyride 515]

Read up a little on hypervisors.  ESXi, ProxMox VE, KVM, XenServer, etc are all hypervisors, which run as the initial boot environment (before an operating system).  Hypervisors manage virtual machines, each of which are completely seperate and independent of each other.  DSM is then run as a virtual machine workload within the hypervisor environment.  We can support NVMe services because they are managed completely outside of the DSM VM.

 

DSM has the ability to act as a hypervisor (VMM), but this is not useful to support NVMe drives (since DSM doesn't support them in the first place).

 

Docker is not a hypervisor, it's an aliased environment within Linux.  Docker apps share the same Linux working environment.  You might think of it working in the same way as a hypervisor, but it is quite different.

 

It is possible to import your baremetal XPe DSM system into an ESXi VM, but that is a technically demanding task and you should be very familiar with XPe and running it under ESXi before attempting it.  So yes, you would probably need to plan to "start over" and import your data once everything was set up and tested under ESXi.

[Vodka2014 8]

Thanks @flyride

 

I think I will just remove the M.2 and use it for something else in the meantime until I have an better understanding and read up on all of this.

 

Thanks again for you help. 

[bobss 0]

Does anyone know if DSM is ever going to support M.2 NVME SSD as MAIN storage? Does it work on DSM7 ? Or are there any hacks to get this working?

[flyride 515]

On 1/13/2021 at 10:22 PM, flyride said:

Your best functional option to use NVMe with DSM is to install DSM within a hypervisor (ESXi), which can then virtualize and syndicate the NVMe storage to DSM as a VMDK (virtual disk image) or RDM (raw device mapping).  RDM is preferable as it performs better, gives you 100% of the space and the device can be directly attached to a virtual SATA controller so it appears as SATA to DSM.