Seafile server 6 on Raspberry pi v3: slow sync or normal behavior?

I have installed Seafile server 6.0.7 on my raspberry pi v3 that is connected to the lan through ethernet.
I’m using it through an https connection managed by ngynx.
The seafile data directory is on a 256GB USB 3.0 flash key mounted with ntfs-3g. I know that USB keys are not reliable for long term storage but I’m using it as a copy of my photo archive folder that resides on my local windows PC (that I backup elsewhere).

I’ve not transferred the whole archive yet (160Gb) but instead I’m gradually adding folders. Since yesterday I began synchronizing a folder containing 19Gb with 4000 files in 100 folders and it is not finished yet. Most of the time the windows client says uploading 0% and time to time it uploads a few files at 4Mb/s.

According to the task manager there is available RAM and the cpu usage never exceeds 50%: what is bottlenecking my installation?
Am I pushing the raspberry beyond its limits or is there a way to optimize the setup in some way (i.e. by formatting the USB key in ext4? attaching an SSD or an HDD instead of the USB flash key?)

thank you for attention,

The Pi’s ethernet runs on the USB bus, and it only has a 100Mbit ethernet controller anyway. The USB itself is 2.0 only. So you won’t get more performance here.
Better use a Cubietruck or ODROID-XU4 for NAS purposes.

1 Like

Thank you for your answer.
It turned out that the ntfs-3g was slowing down considerably the access to the usb key (but apparently not to a ntfs hdd). I reformatted the usb key with ext4 and now it appears to reach 3Mb/s transfer rate.
EDIT: after a couple of days of adding files on the key the behavior is the same as before. The folder is now 100Gb. I would need to transfer to an hdd and check if it is the usb flash key fault or the raspberry access time to such a huge storage folder.