OSx Server local network bandwith slowdown when Seafile Client in sync

I use Seafile to sync two OSx servers located on two differents sites and get a cloud access to the synced folders.
The Seafile server (5.1.4) is outside the company running on an Ubuntu LTS 16.04.
On my locals networks, servers are OSx 10.9.5 server running Seafile Client 5.1.4.
Around 2To of datas synced.

Everything works great except when the client is syncing.

The local network transfers can drop from 100Mo/s to 1Mo/s, it’s very hard to download or view a file from the server, impacting all the workstations. Strangely, the server can upload to a workstation correctly. When the sync is finished, everything return correctly.
The Osx servers are 2x2.8 quad-core xeon with 16Go ram with 2gb ethernet trunk and are used at 15% max.
Today, I have programmed to start/stop the clients at low activity hours. I have made all the updates from version 4 and stopped since no difference to version 5.1.4

Have you already experienced this case ?


Looks like a bad router.

Thanks for the answer. But I don’t think it’s a router problem as everything work fine until the Seafile Client is launched. For myself, I think that the seafile process take the same core processor than the smb/afp process putting one at 100% and leave the others at 0% like no use of multithreading .

This is interesting to me because I run a (external) Seafile CE 6.2.2 server on Ubuntu 16.04 that serves a Mac-centric network with OS X server and am not seeing slowdowns like you describe.

The Seafile server originated in v. 4.0 and has been upgraded all along to 6.2.2. For the most part Seafile clients are up-to-date. The Mac OS X server is 10.11.6, I believe. Mac users are mostly 10.11 with some 10.12.

I am not syncing the Mac server with Seafile, however. Only the Mac clients use the Seafile server.

Can you describe how you measure network transfer? Is the basic idea behind your setup that one Mac server backs-up to another via Seafile?

Why does that exclude the option? Before launching Seafile there is no network load and after launching Seafile it synchronizes and there is load …

Is everything via LAN or is Wi-Fi also being used?

Hello, thanks for the contribution.
My configuration looks yours but the difference is that i have only one Seafile Client installed on the OSx Server, not on any Mac Client.
When the Seafile Client is syncing on the OSx Server all the file access from the client side on the wired local network are really slowed down.
To monitor, I simply use the Activity Monitor on the Network tab or the MenuMeters app, I look on Mac client for a large file on the Mac Server (mounted as AFP or SMB) and copy to the desktop, the transfer and reach the max bandwith of the gigabit connection (env 100 Mo/s) then I start the Seafile Client on the server, syncing begin, the transfer reach 2Mo/s, exiting the Seafile Client and transfer return to 100Mo/s.

The Seafile Client is installed on an OSx Server, all the local network is wired thru gigabit ethernet.
The Osx Server is connected to the master switch with 4gbit trunk (4x 1gbit agreate link) to avoid bottleneck.
As it’s a server, there is always network load on it because it’s serves about 30 mac clients. All the datas transfers initiates from mac clients to the Osx server work fine until the Seafile Client begin it’s syncing process.

In your original post you say that each OS X server is located at different sites. From that can I conclude that they are on completely different networks? Same for the Seafile server?

Are the two OS X servers syncing to the Seafile server sharing the same folder(s)? or does each have its own set of folders that it sync?

Sorry, but I need to be clear in case I can replicate the setup.


Your conclusion are right. The two Osx server and Ubuntu Seafile Server are on completely different network. The setup of network architecture on the two sites is almost the same and i experiment the same troubles on both. The two Osx servers shared the same folders (2 in fact) to the seafile server making the servers in sync an have the ability to get some outside the company workers to have access to datas stored on those folders. Here a quick drawing of the setup.


Sorry for the delay in getting back to you. I’ve been able to replicate the OS X Server sync using two macOS El Cap (10.11.6) servers and a Seafile CE 6.2.3 server running on Ubuntu 16.04.3.

The networking architecture is pretty much the same but we have obvious differences in the versions of Mac OS and Seafile server. The bottom line is I do not see a slow-down in downloads during syncs.

I first tried syncing one OS X server client and tested a download while the sync was in progress; then repeated the same download while both servers were syncing. No change. Just for reference, the downloading client is a Mac using AFP on the LAN of the first server.

Anything you want me to try as a test, please do not hesitate to let me know.


Thank you very much for this test, that’s encouraging! It really looks like my setup.
I’m going to see to update everything soon and see if that changes.
In this kind of configuration, what would you do in which order for updates? The server first? Do clients have to be disconnected during this update? When updating clients, is there a particular procedure?
Best regards

First, I would do full backups of all the servers (Clonezilla, Redo, Carbon Copy Cloner). To my mind the upgrades are full of peril and you might want the option to roll back in a hurry.

Following that, I would upgrade the Seafile server first. The Seafile client computers are fairly modern so you should have no/few problems with them while you upgrade the client software. I would quit the client software prior to the server upgrade.

Next upgrade the OS X Servers focusing first on the “source” or master server if there is one. Make sure you backup the OpenDirectory databases (and export Users & Groups data) before you begin the upgrade. You might need them! I find Apple’s OD is a bit troubled at times.

One other thing: You might want to avoid High Sierra for the present if you can. APFS might introduce a variable into the equation that is hard to deal with.

Good luck!