Ask Your Question

Revision history [back]

SMB Transfer Upload fast, Download slow

I have problems within my local network.

I have a Windows Server 2019 with some shares (no Active Directory). Clients are all Windows (mostly Windows 10). No virtualization is being used.

Uploading files to the share is pretty fast, about 60 MByte/sec. But downloading files from the share is extremely slow, between 1-4 MBytes/sec. These results come from a wifi connection but are similar using an ethernet connection. So it is not a wifi problem.

You find the captured results here: Download: https://1drv.ms/u/s!AphLkdj_V9pOpTL2DGVJl97pZioL Upload: https://1drv.ms/u/s!AphLkdj_V9pOpTHs9SulooKV3gd3

I noticed quite a lot TCP Dup Ack, Out-Of-Order and Retransmission packets.

Turning off Windows Defender and Firewall on the client did not change anything.

Using iperf, i measured the bandwith between client and server: - Download: 20 Mbit/sec - Upload: 1 Gbit/sec (ethernet), 300 Mbit/sec (wifi) So it seems not to be an SMB problem.

Does anybody has an idea what the reason could be or how I could investigate further?

SMB Transfer Upload fast, Download slow

I have problems within my local network.

I have a Windows Server 2019 with some shares (no Active Directory). Clients are all Windows (mostly Windows 10). No virtualization is being used.

Uploading files to the share is pretty fast, about 60 MByte/sec. But downloading files from the share is extremely slow, between 1-4 MBytes/sec. These results come from a wifi connection but are similar using an ethernet connection. So it is not a wifi problem.

You find the captured results here: Download: https://1drv.ms/u/s!AphLkdj_V9pOpTL2DGVJl97pZioL Upload: https://1drv.ms/u/s!AphLkdj_V9pOpTHs9SulooKV3gd3

I noticed quite a lot TCP Dup Ack, Out-Of-Order and Retransmission packets.

Turning off Windows Defender and Firewall on the client did not change anything.

Using iperf, i measured the bandwith between client and server: - server:

  • Download: 20 Mbit/sec - Mbit/sec
  • Upload: 1 Gbit/sec (ethernet), 300 Mbit/sec (wifi) So it seems not to be an SMB problem.

Does anybody has an idea what the reason could be or how I could investigate further?

SMB Transfer Upload fast, Download slow

I have problems within my local network.

I have a Windows Server 2019 with some shares (no Active Directory). Clients are all Windows (mostly Windows 10). No virtualization is being used.

Uploading files to the share is pretty fast, about 60 MByte/sec. But downloading files from the share is extremely slow, between 1-4 MBytes/sec. These results come from a wifi connection but are similar using an ethernet connection. So it is not a wifi problem.

You find the captured results here: Download: https://1drv.ms/u/s!AphLkdj_V9pOpTL2DGVJl97pZioL Upload: https://1drv.ms/u/s!AphLkdj_V9pOpTHs9SulooKV3gd3

I noticed quite a lot TCP Dup Ack, Out-Of-Order and Retransmission packets.

Turning off Windows Defender and Firewall on the client did not change anything.

Using iperf, i measured the bandwith between client and server:

  • Download: 20 Mbit/sec
  • Upload: 1 Gbit/sec (ethernet), 300 Mbit/sec (wifi) (wifi)

So it seems not to be an SMB problem.

Does anybody has an idea what the reason could be or how I could investigate further?

SMB Transfer Upload fast, Download slow

I have problems within my local network.

I have a Windows Server 2019 with some shares (no Active Directory). Clients are all Windows (mostly Windows 10). No virtualization is being used.

Uploading files to the share is pretty fast, about 60 MByte/sec. But downloading files from the share is extremely slow, between 1-4 MBytes/sec. These results come from a wifi connection but are similar using an ethernet connection. So it is not a wifi problem.

You find the captured results here: Download: https://1drv.ms/u/s!AphLkdj_V9pOpTL2DGVJl97pZioL Upload: https://1drv.ms/u/s!AphLkdj_V9pOpTHs9SulooKV3gd3

I noticed quite a lot TCP Dup Ack, Out-Of-Order and Retransmission packets.

Turning off Windows Defender and Firewall on the client did not change anything.

Using iperf, i measured the bandwith between client and server:

  • Download: 20 Mbit/sec
  • Upload: 1 Gbit/sec (ethernet), 300 Mbit/sec (wifi)

So it seems not to be an SMB problem.

Does anybody has an idea what the reason could be or how I could investigate further?

EDIT: Network topology between Client and Server:

  1. Client (wifi)
  2. Router
  3. Switch 1
  4. Switch 2
  5. Server