What should I do if I'm experiencing Slow File Transfer issue?

Applicable Products:

• All NAS series

If you are experiencing slower than usual file transfer speed, you may run some tests to narrow down the root cause.

Please find below what you could do, depending on your issue:

The following factors may slow down the speed

• An encrypted shared folder/volume/external drive may slow down the speed, please run the speed test on a unencrypted shared folder/volume/external drive.
• SMB Encryption may slow down the speed, please disable SMB encryption Privilege > Shared Folders > Shared Folder> Property.
• Server Signing may slow down the speed, you can find Server Signing setting in Privilege > Domain Security.
• SSD cache acceleration accelerates the frequently accessed data, recommend disabling SSD cache acceleration and create a static volume on the SDD disk then perform the speed test.

Perform Internal test

Follow the steps below to estimate the internal speed NAS could provide.

• Check Disk raw Read Speed

  1. Log in to QTS as an administrator
  2. Open Control Panel
  3. Go to Storage & Snapshots > Storage > Disk/VBOD> Performance Test
  4. Perform Sequential Read Test
  5. Check the read speed, normally Disk read speed should provide over 100MB/s.

• Examine the RAID performance

  1. SSH access the NAS
  2. Use the command qcli_storage -t force=1
  3. Check FS_throughput that file system can provide, this value may depends on the disk speed and RAID type you are using.

• You may refer to the Product Performance examined in QNAP lab and compare the sample setup in the lab.

Perform external test

1. Slow transfer speed over the network (WiFi/Ethernet/Thunderbolt connection):

Set up a direct connection between NAS and computer using ethernet cable or thunderbolt cable, and compare the speed when transferring a large file.

Please note that copying multiple folders with a bunch of files would drastically reduce the overall speed. We can usually compare the transfer speed by using a very large file. You may click here to download the test file. (4GB size big is recommended)

The upload/download speed is expected to be

• Around 12 MB/s in a direct 100Mbps wired Ethernet connection.

• Around 100 MB/s in a direct 1Gbps wired Ethernet connection.
• Around 100MB/s - 1000MB/s in a direct 10Gbps wired thunderbolt/Ethernet connection.
• Around 200Mbps equals 24MB/s in a wireless 802.11ac wireless connection, normally the bottleneck of wireless connection is on the router, do a direct connection using ethernet cable is recommended.
• Around 100Mbps equals 12MB/s in a wireless 802.11n wireless connection, normally the bottleneck of wireless connection is on the router, do a direct connection using ethernet cable is recommended.

If the original transfer speed is significantly lower than in direct connection, that may be due to:

• Network connection -> it is recommended to contact the router manufacturer, or your ISP.
• Defective Ethernet cables -> you may as well use a different cable to test the speed.

2. Slow transfer speed over USB

Please copy first the large file to any of the NAS folder.

Then you can compare the transfer speed when copying the file to the external drive, either by File Station or Hybrid Backup Sync.

The root cause could be:

• Compatibility issue -> please make sure the external USB device is listed as compatible with your NAS model: https://www.qnap.com/en/compatibility/
• USB device failing -> please try with several other devices and compare the results.