Ubuntu slow transfer speeds with Recovered RAID 6

[roberts_zak]

Hello everyone - I apologize if this is a question for elsewhere, please let me know if it needs to be moved.

We recently had a Thecus n7700pro get the corrupted DOM and get stuck on "Self Testing..." screen. This is a 7-Drive, RAID 6 setup, each disk being a WD RED witth 3TB, giving us roughly ~15TB usable space, ~13TB used.

So, I took out all of the hard drives, and plugged them all into my old-ish gaming PC (AMD-8350, Sabertooth 990FX R2, 16GB RAM), and installed Unbuntu onto the system on an 8th drive (this fills up my SATA slots on the board).

I was following a tutorial on a thecus thread, and installed mdadm along with lvm, and after reboot and plugging in all 7 drives, I can see my RAID array and access the data.

I am now attempting to transfer files over onto an external, USB 3.0 6TB Harddrive in chunks, and migrate them onto the new NAS that will be arriving shortly (8-bay synology with 8x6TB IronWolf's). The problem is, my transfer speeds are insanely slow. I am getting around ~500KB/s to 1.2MB/s, causing a 230GB transfer to be estimated at around ~100 hours.

Are there any suggestions on how to potentially help speed this up? I've gone into the BIOS, and I've made sure USB 3 is enabled, I've also gone in and turned on IOMMU along with EHCI. And, when copying files that are not on the RAID array, i do get closer to 50MB/s transfer speeds, so my fear is that I'm just at the limit of what the board can handle.

As always, really appreciate any suggestions or help on this.
Thanks!

 

[kanewolf]

On Ubuntu, you should format the external drive to EXT4 rather than NTFS.

 

[roberts_zak]

I'm sorry for the late response on this - I didn't see the notification in my inbox.

I've tried re-formatting the external USB drive to EXT4, still having similiar speeds. I've also tried switching over to an eSATA based docking station that was formatted to EXT4, and copying directly to the Ubuntu boot drive, speeds still around the 500KB/s speeds. It appears the bottle neck is either hardware based with the SATA controller on the board (i've never experienced this, but i've never filled it up before either?), or with how mdadm is setup.

Appreciate the assistance!

 

[roberts_zak]

Hey Everyone -

Just wanted to follow up on this. The cause was because the RAID was degraded, I have a thread on the unix/linux stack exchange that goes into more details of showing how we came to this realization, and how I went about adding an additional drive back into the Array to repair it.

After doing all of that, my transfer speeds went back up to a much more manageable ~50-60MB/s.