Data transfer speeds nosediving

[goldenEY3]

Hello all, new Unraid user here trying to land on their feet.

 

I moved from TrueNAS to Unraid to take advantage of the Docker feature and expand my NAS' usefulness. However, once I got everything installed and started moving data over, the transfer speeds took an immediate nosedive.

 

Transfers went from 100+ MB/s to sub-10 MB/s within seconds of moving files. I know my equipment and network are good, because when I was running TrueNAS, transfers were rock-steady and above 100 MB/s. Now, it's taking far too long to move even the most basic amount of data to the array.

 

I've done some searching in the forums about this issue, and it seems the most common fix is to enable Turbo Write. I've enabled it, rebooted the machine (from the Web GUI), yet the issue remains; starts at 100+ MB/s, then gets cratered to sub-10 speeds. 

 

Is there a setting I'm missing or overlooked?

[trurl]

Attach Diagnostics to your NEXT post in this thread 

[goldenEY3]

9 minutes ago, trurl said:

Attach Diagnostics to your NEXT post in this thread 

Thanks, trurl. Hope this helps in finding a solution.

 

 

tower-diagnostics-20220422-0941.zip

[JorgeB]

Disks 1 and 3 are SMR, try transferring to disk2, it should be faster.

[goldenEY3]

3 hours ago, JorgeB said:

Disks 1 and 3 are SMR, try transferring to disk2, it should be faster.

First, thank you for the help.

 

I adjusted the share setting to "Include Disk 2," tried transferring ~10 Gb of files to the NAS. It transferred half at 100+ Mb/s, then dropped down to ~50 Mb/s; I'm willing to chalk that up to the cheap backup storage disk I'm using to hold my data until I get the transfer thing sorted out. That adjustment seems to have worked.

 

Do I have the right to assume that SMR hard drives don't doesn't play well with Unraid?

[trurl]

1 minute ago, goldenEY3 said:

tried transferring ~10 Gb of files to the NAS. It transferred half at 100+ Mb/s, then dropped down to ~50 Mb/s

Probably the beginning speed was due to RAM buffering, so you get full network speed, then it had to actually write to the disk and update parity.

[JorgeB]

12 hours ago, goldenEY3 said:

Do I have the right to assume that SMR hard drives don't doesn't play well with Unraid?

 

SMR drives can have slower writes with everything, including Unraid, though some drives perform better than others, I have some Seagate SMR drives that basically perform as CMR, WD and Toshiba SMR drives can be a lot slower, I have an SMR array where writes are as low as <5MB/s for a few minutes frequently.

[itimpi]

15 hours ago, goldenEY3 said:

Do I have the right to assume that SMR hard drives don't doesn't play well with Unraid?

As was mentioned SMR drives perform the same regardless of OS.  In fact since Unraid is often used as a media server SMR drives can be OK as array drives if you do not write large amounts of data to the same drive in a short period of time so you do not exceed the drive cache and see the write slowdown penalty.  At one time there was a significant price advantage to using SMR drives although I think this is no longer so pronounced.

[goldenEY3]

Think things are pretty well solved.

 

Bit the bullet and upgraded my drives; swapped out the WD Reds for Seagate IronWolf NAS drives. I was probably gonna have to expand anyways.

 

Local store had a deal for SSDs on the cheap, so I picked up an NVMe to use as a cache drive.

 

Between the cache and the new (non SMR) drives, transfer speeds are holding rock steady at 100+ Mb/s. 

 

tl;dr solution: unmarked SMR drives killed data transfer speeds, upgraded to drives that don't use SMR, issue resolved.