Allowing Multipart Transfers (COMB Command)

EFT supports multi-part transfers from advanced FTP clients such as CuteFTP. The user must have appropriate privileges and be authorized to connect multiple times Setting Maximum Connections per User. The connecting client takes care of most details, including splitting the file apart, sending the multiple parts, and then requesting that the Server to join them again upon receipt.

To allow or block multipart transfers

  1. Open the FTP Settings dialog box.

  2. Do one of the following:

    • To allow transfers, select the Allow multi-part transfers (COMB) check box.

    • To block transfers, clear the Allow multi-part transfers (COMB) check box.

  3. Click OK to close the FTP Settings dialog box.

  4. Click Apply to save the changes on EFT.

How does the COMB command work?

The COMB command joins the parts back together. The benefits of segmented (multi-part) and concurrent delivery for accelerated transfers include:

  • Accelerate throughput and maximize available bandwidth available to the client by allowing uploaded files to be split apart and transferred in multiple segments simultaneously.

  • Command can be toggled on or off.

The COMB command is a proprietary command and is not defined nor endorsed by any FTP-related RFC; however, the command can be integrated with other servers using the following syntax:

COMB <TF> <SF 1> ... <SF n>

where

<TF> is the path to target file, which will contain the combined data from the source parts.

<SF #> are the source files (parts).

Which means combine n source files (SF 1...n) into one file (TF).

Notes regarding the COMB command:

  • If the target file already exists, then EFT appends source files to it.

  • EFT will delete all the source files once they are combined successfully.

  • All file names should be in quotation marks.

  • Upload, download, append, and delete permissions are REQUIRED, otherwise COMB will fail.

    • Upload and Append permissions are checked for the target result file.

    • Download and Delete permissions are checked for the source parts that are read for the COMB into the target result file.

    • Cleanup (delete) is performed on the target result file if an error occurs accessing the source parts.

Examples of using the COMB command:

  • You can append a single part onto an existing (or new) file: e.g., COMB "final.log" "132.log".

  • Paths are accepted for the target filename, but not for source parts file path. For example:

    • COMB "boslin/blah/final.log" "70.log" "71.log" "72.log" "73.log"

  • There is no limit to the number of parts, but there is a server-side processing limit of approximately 1024 characters.

  • A space is not required between quote-delimited file names. For example:

    • COMB "final3.log""60.log"

    • COMB COMB "final3.log" "60.log"

  • Target and source files do not require enclosing quotes UNLESS the filename includes spaces. In that case you should use quotes. For example:

    • The following syntax is correct:

      • COMB final5.log 64.log 65.log

      • COMB "final5.log" "64.log" "65.log"

      • COMB final7.log "6 6.log" 67.log

    • The following syntax will not work because the filename includes spaces:

      • COMB final6.log 6 6.log 67.log