Knowledgebase: Cloud Solutions
Advisory: Limitations using External Cloud Storage with FileCatalyst Server
Posted by Aly Essa, Last modified by Aly Essa on 24 May 2021 09:32 AM


The FileCatalyst Server supports writing to external file systems. Our application can read and write directly to these cloud-based storage vendors by adding them to the User account on the FileCatalyst Server. The following is a list of storage vendors we currently support:

  • Amazon S3
  • Azure Blob
  • OpenStack Swift
  • Google Cloud Storage
  • Backblaze B2
  • Wasabi
  • Dropbox (Labs)

We recognize that there are many vendors who support specific feature sets, however, we would like to advise our clients using any Cloud Storage to configure your tasks without using the following features:

  • Basic and Advanced Progressive Transfers (HotFolder)
  • Transfer File Delta (HotFolder)
  • Transfer Files using Incremental Modes (HotFolder and TransferAgent Express)
  • Auto-Resumes or Overwrites (All Clients)
  • Zipping (All Clients)
All the features mentioned above use the FTP command APPE (append) which means that there will be a file fragment that will have more blocks written to it. Using the features listed above could also leave orphaned files in your storage bucket which is not always visible or accessible by our software. These files are visible using the Native Storage Browser from the vendors and will need to be removed manually to prevent you from being charged with extra fees.

All of the limitations that are placed on External File Systems transfers using FileCatalyst Products are available Section 13: External File Systems page of our Server Documentation:

Please note the link above requires a download password. You can obtain this by logging into the Support Portal and clicking on Get Download Credentials button in your profile. Alternatively, you can access the documentation from the Help menu from your Server Remote Administration application.


Where possible please avoid the features listed above when configuring your transfer options and tasks.