F4-423 SMB transfer's speed from PC stops every few seconds

[Lisko]

Hi, I currently have a new f4-423 with only a 4TB Seagate ironwolf formatted in btrfs and traid because I plan to put other drives shortly. I'm on tos 5.1.37. The PC it's connected to the same Ethernet switch of the tnas. Downloads from the nas are at full Gbit speeds. The problems arises when uploading to the nas. The transfer starts at full speed but after few seconds the transfer rate drops to 0 for 1-2 seconds and then goes again in full speed and after some seconds it drops to 0 again and this repeats until the transfer is over. It does the same even with mac clients or FTP. The issue seems very like this one: viewtopic.php?t=1274
I'm liking this nas but it's not very useful right now and I hope this can be fixed otherwise I'll have to return it.

[RyanYang]

Have you ever tried uploading only one large file? Will speed also experience such fluctuations?
How long have you been using your hard drive?
Perhaps you can try going to the volume page of the TOS control panel to perform a file system defragmentation.
Please do not shut down the system until the file system data is cleaned up.
If the system shuts down before completion, it must perform file system defragmentation from scratch again.

[TMroy]

Please make sure that the hard disk in your TNAS, the hard disk of your PC, or the network is working properly. As for NAS, as long as the network is normally connected, such a speed drop will generally not occur.

[Lisko]

Have you ever tried uploading only one large file? Will speed also experience such fluctuations?
How long have you been using your hard drive?
Perhaps you can try going to the volume page of the TOS control panel to perform a file system defragmentation.
Please do not shut down the system until the file system data is cleaned up.
If the system shuts down before completion, it must perform file system defragmentation from scratch again.

Yes even with one large file. The hard drive is new and there was nothing on it so it's not due to fragmentation. The network it's good because when downloading from the nas I get full and consistent speed. I also deactivated the hypercache on my 128GB nvme ssd because it amplified a lot the issue even in read-only mode.

[TMroy]

A speed drop could happen when:
1. network fails
2. NAS hardware fails(including motherboard and SATA connection)
3. NAS software fails
4. hard drive on NAS fails
5. hard drive on PC fails
6. Files being transferred are corrupted

As you said, you can download at full speed, so No. 1& 2 could be excluded. SMB file service in 5.1.37 has been verified by many users without issue.
So I recommend you verify No. 4, 5, 6.