Question Erratic Transfer Speeds to Home-Build Truenas NAS

Sep 20, 2022
5
0
10
0
Hi all,
So I have a a custom truenas NAS with three 8tb disks in Raid-z. When it works, it works very well. I have a windows laptop so I'm using the fastest adapter I could find (QNAP 5gbe) which despite because 5gig actually maxes out at around 3.5gbe. Which is fine for me. Most of what I'm doing is moving around large video files for my small business.
When it works, it will hit the 3.5gbe sustained and complete the job without issue.
When it doesn't work, accessing the file share through explorer becomes laggy (blue loading cursor appears when clicking into a folder, etc) and the transfer speed will go from max 3.5gbe all the way down to zero. Like a rollercoaster.
At first I thought it was the adapter malfunctioning, but I switched to using the inbuilt 1gbe adapter on my laptop and it does exactly the same thing, going from the peak of 1gbe down to zero.
It's very strange and nothing in particular seems to trigger the works fine / serious instability switch. If anyone has any ideas / suggestions would be much appreciated!
 
Storage area networks is one of the highest paying networking jobs there is because of the complexity involved where you must know the network part but also the file/data part.

There are so many parts here that can cause this. It tends to not be network when you are running very simple lan like you are.

This looks like some kind of issue with the way the files are stored onto the disk array. You would think there are performance testing tools on the nas....then again part of the reason commercial NAS cost so much money is this extra software that makes it easy to administer. I would first see if there is any kind of diagnostic messages in the nas unit that flag some kind of error. Something very bad like a disk failing to read should show up.

If like most NAS this is built on some form of linux you should be able to load a test program called IPERF. This should let you test the network part of your system without using disks.

Now the problem could also be on the laptop side. Could be some issue with the disk system there. A laptop generally even with a SSD is not a high performance disk system.

Likely the reason you only get 3.5g is you are using a USB interface these tend to have lots of overhead.

Do other devices have similar issues access the NAS, that should give you a clue if it is the end machine or the NAS. If you only have a single machine accessing this NAS you likely would have been better off just building a large desktop machines with lots of internal storage to do the function. A NAS generally is used when you have many machine needing to access the same data.
 

palladin9479

Distinguished
Moderator
Hi all,
So I have a a custom truenas NAS with three 8tb disks in Raid-z. When it works, it works very well. I have a windows laptop so I'm using the fastest adapter I could find (QNAP 5gbe) which despite because 5gig actually maxes out at around 3.5gbe. Which is fine for me. Most of what I'm doing is moving around large video files for my small business.
When it works, it will hit the 3.5gbe sustained and complete the job without issue.
When it doesn't work, accessing the file share through explorer becomes laggy (blue loading cursor appears when clicking into a folder, etc) and the transfer speed will go from max 3.5gbe all the way down to zero. Like a rollercoaster.
At first I thought it was the adapter malfunctioning, but I switched to using the inbuilt 1gbe adapter on my laptop and it does exactly the same thing, going from the peak of 1gbe down to zero.
It's very strange and nothing in particular seems to trigger the works fine / serious instability switch. If anyone has any ideas / suggestions would be much appreciated!
Did you build the TrueNas device, what kind of memory and CPU does it have? When you configured the storage pools, did you leave compression on or enable deduplication? ZFS is an amazing file system capable of crazy awesome things, those features come at the cost of requiring much higher system resource then people are used to thinking. What you can do is have the TrueNAS status page up and monitor CPU utilization, or SSH into it and run "top" to watch CPU process's. Then start copying / moving data around and watch what happens. If the CPU utilization starts slamming high values then it's likely being taxed with having to do the calculations for redundant file storage and compression.

I use TrueNAS on my own home storage system with a 10Gbe intel NIC connected to a 10GBe switch and an ESXi server that also has a 10GbE adapter for iSCSI volumes and regular SMB file shares. It's using an older A8-7600 I had laying around with 16GB of memory, that 4 core GPU can and will hit 100% if I start doing compression or deduplication.
 

ASK THE COMMUNITY