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Maximizing SFTP Performance

SFTP has bad performance characteristics due to limitations in the design of the protocol. The single biggest piece of advice we can give you is to not use SFTP at all.

For file transfers to and from Files.com, we strongly recommend the Files.com Desktop App or one of the other options listed on our Preferred Apps for File Transfer page. These native apps are many times faster and more reliable than SFTP.

If your situation does not allow the use of one of our preferred apps, or if you are required to use SFTP by a vendor or counterparty, the steps below will help you get the most out of SFTP.

Maximize the Buffer Size (Data Chunk Size) in Your SFTP Client

Most SFTP clients send data in chunks of 32 kilobytes. That is a very low size for today's internet.

We recommend increasing this size by 4-32x in your client. Tuning it requires some trial and error in SFTP. Other protocols handle this process much more automatically.

If you are using the command line sftp tool, you can set the buffer size using the -B option: sftp -B 128000 username@MYCOMPANY.files.com

If you are using any other client, look for settings related to buffer size or data chunk size and crank them up.

Use Many Parallel Connections

Set the number of simultaneous connections to 10-25 or the maximum supported by your SFTP app.

To increase the number of simultaneous connections in FileZilla, go to Edit > Settings > Transfers and increase the Maximum simultaneous transfers setting to 10.

To increase the number of simultaneous connections in Cyberduck, first go to Edit > Preferences > Transfers and set Transfer Files to "Open multiple connections".

Then, go to Window > Transfers and increase the counter in the lower right to the maximum.

Increasing the number of simultaneous connections will help when uploading multiple files at the same time but will not have any effect when uploading a single file.

Minimize Network Latency

Network latency is measured as the round-trip delay between sending data across a network and receiving a reply that the data was received. Higher latency, also known as "lag", can be caused by:

  • physical limitations, such as your physical network connection.
  • how much data is currently saturating your network connection.
  • the network distance between you and your destination.
  • network tools and software that regulate or restrict bandwidth usage.

Network latency has a large impact on SFTP performance. Whenever possible, use the best physical network available to you and achieve the shortest network distance possible.

Use the Best Physical Network Available to You

Choose a physical ethernet connection over a Wi-Fi connection.

Use the Shortest Network Distance Possible

Connect from the same geographic region as the destination. Using VPNs or network proxies located in other geographic regions always adds latency. For example, if you are located in the EU and the SFTP destination is also located in the EU, but your VPN is located in the US, all your data will be routed through the US. That causes much higher latency despite the SFTP destination being geographically close to you.

Multi-Region or Remote Server Mount Considerations

Files.com supports accessing files stored in multiple regions or on multiple remote servers from one unified SFTP connection. That capability is powerful, and it also creates performance challenges in SFTP.

When accessing files in multiple regions or on multiple remote servers from one single connection, we recommend switching to a Files.com CLI, SDK, or Desktop app, which are optimized for multi-region scenarios.

Custom Domain Considerations

If you are using a custom domain with Files.com, note that custom domains are always hosted in a single region. If you are not physically located near the region where your custom domain is hosted, SFTP performance will be very poor.

We recommend testing connections to app.files.com rather than your custom domain if you are trying to use SFTP from a region other than the one where the domain is hosted. That can increase SFTP performance by reducing network latency dramatically. The app.files.com domain is available in many different geographies. This option is available only if your Files.com site does not use a Custom Namespace or require inbound connectivity to be in a certain region.

Performance is worse still when a Files.com site's custom domain is in one region, you are accessing files located in another region, and your SFTP client is in a third region. In cross-region cases like that, we recommend switching to a Files.com CLI, SDK, or Desktop app, which are optimized for multi-region scenarios.