Ascp4 Transfers with Object Storage

Files that are transferred with object storage are sent in chunks through Trapd. By default, ascp4 uses 64 KB chunks and Trapd uses 1 MB chunks, but this mismatch in chunk size can cause ascp4 transfers to fail.

To avoid this problem, take one of the following actions:

  1. Set the chunk size (in bytes) in the server's aspera.conf. This value is used by both ascp4 and Trapd, so the chunk sizes match.
    To set a global chunk size, run the following command:
    > asconfigurator -x "set_node_data;transfer_protocol_options_chunk_size,value"
    Where value is between 256 KB (262144 bytes) and 1 MB (1048576 bytes).
    To set a chunk size for the user, run the following command:
    > asconfigurator -x "set_user_data;user_name, username;transfer_protocol_options_chunk_size,value"
  2. Set the chunk size in the client's aspera.conf to the Trapd chunk size.
    If Trapd is using the default chunk size, run the following command to set the chunk size to 1 MB:
    > asconfigurator -x "set_node_data;transfer_protocol_options_chunk_size,1048576"
  3. Set the chunk size in the client command line.
    Run the ascp4 session with the chunk size setting: --chunk-size=1048576.