Hello,

I am experiencing a data transfer speed problem I hope somebody in the community can clarify for me. I have my Windows RAID6 PC and my new UnRAID NAS connected peer to peer using two MCX311A-XCAT ConnectX-3 cards. On my UnRAID NAS I set the Mellanox MTU found in Network Settings to a 9000 value.  I also set my Windows RAID6 PC Jumbo Packet parameter to 9000.  In short, my data transfers start great at around 900 MB/s but after 30 or so seconds it drops down to around 75 MB/s.  Why does it drop?

 

Is it because I am not using a Cache Disk? The files are being moved from my RAID6 Array located in my old Windows PC over to my new UnRAID NAS share via a Mellanox peer to peer connection. Is 75 MB/s data transfer speed the best speed I can expect  if I am not using a Cache disk?  I honestly thought setting up two Mellanox cards would give a much faster speed than the 75 MB/s I am getting. 

 

Also, does my UnRAID v6.8.3 OS support SMB3?  I tried looking for it in the Windows SMB setting  and could not find a SMB3 setting under the Settings Tab in the UnRAID OS.  I'm trying to learn how to change my UnRAID OS from SMB to SMB3 so I can get a faster speed.  I hope somebody can give me some advice on how to make a change to SMB3.  

 

Any advice will be greatly appreciated.  Thank you for your time.

 

 

 

 

You should be able to get improved performance if you enable turbo write, but Unraid doesn't stripe disks, so writing to the array can never be faster than your slowest disk, you can get better speeds writing to a fast cache device or pool.

18 hours ago, slipstream said:

In short, my data transfers start great at around 900 MB/s but after 30 or so seconds it drops down to around 75 MB/s.  Why does it drop?

...RAM buffer is full and your Parity-Assisted Array will not perform physically faster...as already explained above.

 

18 hours ago, slipstream said:

Is it because I am not using a Cache Disk? The files are being moved from my RAID6 Array located in my old Windows PC over to my new UnRAID NAS share via a Mellanox peer to peer connection.

 

If this is the "initial load" from your Backup to unRaid, as you already know/need to assume that your backup is not corrupted, you could also remove parity from the array until the initial load is finished....when copying data with more than one stream, speed of individual disks can be used simultaneously, hence adding up and improve overall speed.