Maximizing SFTP Performance

In general, SFTP has bad performance characteristics due to limitations in the design of the protocol.

To optimize file transfers to and from, the single biggest advice we can give you is: don't use SFTP at all. Please visit our Preferred Apps For File Transfer page to learn about the native apps that are many times faster than SFTP.

If you are using SFTP to meet the requirements of 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. This is a ridiculously low size for today's internet.

We recommend increasing this size by 4-32x in your client. Unfortunately, this process requires some trial and error to perfectly optimize 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

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 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 try and achieve the shortest network distance possible.

Use the best physical network available to you

For example, choose a physical ethernet connection over a Wi-Fi connection.

Use the shortest network distance possible

Ideally, you should be in the same geographic region as the destination that you are connecting to. Using VPNs or network proxies that are located in other geographic regions will always add latency. For example, if you are located in the EU, the SFTP destination is also located in the EU, but your VPN is located in the US then all your data will be routed through the US which will cause much higher latency despite the SFTP destination being geographically close to you.

Multi-Region or Remote Server Mount Considerations supports accessing files stored in multiple regions or on multiple remote servers from one unified SFTP connection. While this is incredibly powerful and enables many unique capabilities, it can also create performance challenges in SFTP.

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

Custom Domain Considerations

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

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

Performance is even worse when a 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 complicated cross-region cases like this, we really recommend switching to a CLI, SDK, or Desktop app, which are optimized for multi-region scenarios.

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