Data management

• 1: Data transfer

1 - Data transfer

Your Windows Personal Storage and the Project and Group Storage are available on all TU Delft installed machines including the DAIC compute nodes. If possible use one of these for files that you want to access on both your personal computer and the compute nodes. Your Windows Personal Storage and the Project and Group Storage are also accessible off-campus through the TU Delft webdata service. See the webdata page for manuals on using the service with your personal computer.

SCP

Both your Linux and Windows Personal Storage and the Project and Group Storage are also available world-wide via an SCP/SFTP client. This is the simplest transfer method via the scp command, which has the following basic syntax:

$ scp <source_file> <target_destination>       # for files
$ scp -r <source_folder> <target_destination>  # for folders

For example, to transfer a file from your computer to DAIC:

$ scp mylocalfile [<netid>@]login.daic.tudelft.nl:~/destination_path_on_DAIC/

To transfer a folder (recursively) from your computer to DAIC:

$ scp -r mylocalfolder [<netid>@]login.daic.tudelft.nl:~/destination_path_on_DAIC/

To transfer a file from DAIC to your computer:

$ scp [<netid>@]login.daic.tudelft.nl:~/origin_path_on_DAIC/remotefile ./

To transfer a folder from DAIC to your computer:

$ scp -r [<netid>@]login.daic.tudelft.nl:~/origin_path_on_DAIC/remotefolder ./

The above commands will work from either the university network, or when using EduVPN. If a “jump” via linux-bastion is needed (see Access from outside university network), modify the above commands by replacing scp with scp -J <netid>@linux-bastion.tudelft.nl and keep the rest of the command as before:

$ scp <local_file> [<netid>@]linux-bastion.tudelft.nl:<remote_destination>
$ scp -r <local_folder> [<netid>@]linux-bastion.tudelft.nl:<remote_destination>
$ scp [<netid>@]linux-bastion.tudelft.nl:<remote_file> <local_destination> 
$ scp -r [<netid>@]linux-bastion.tudelft.nl:<remote_folder> <local_destination>

$ sftp [<netid>@]linux-bastion.tudelft.nl

Where:

• Case is important.
• Items between < > brackets are user-supplied values (so replace with your own NetID, file or folder name).
• Items between [ ] brackets are optional: when your username on your local computer is the same as your NetID username, you don’t have to specify it.
• When you specify your NetID username, don’t forget the @ character between the username and the computer name.

rsync

rsync is a robust file copying and synchronization tool commonly used in Unix-like operating systems. It allows you to transfer files and directories efficiently, both locally and remotely. rsync supports options that enable compression, preserve file attributes, and allow for incremental updates.

Basic Usage

• Copy files locally:

  rsync [options] source destination
  

  This command copies files and directories from the source to the destination.

• Copy files remotely:

  rsync [options] source user@remote_host:destination
  

  This command transfers files from a local source to a remote destination.

Options in rsync

Commonly used options in rsync with DAIC are:

• -a for recursion and to preserve almost everything
• -z compress file data during the transfer
• -v verbose mode to display information while copying
• --progress show progress of files during transfer
• --no-perms don’t preserve file permissions

In addition to the commonly used options, rsync provides several other options for more advanced control and customization during file transfers:

• --dry-run: Perform a trial run without making any changes. This option allows you to see what would be done without actually doing it.

• --checksum: Use checksums instead of file size and modification time to determine if files should be transferred. This is more precise but slower.

• --partial: Keep partially transferred files and resume them later. This is useful in case of an interrupted transfer.

• --partial-dir=DIR: Specify a directory to hold partial transfers. This option works well with --partial.

• --bwlimit=KBPS: Limit the bandwidth used by the transfer to the specified rate in kilobytes per second. Useful for managing network load.

• --timeout=SECONDS: Set a maximum wait time in seconds for receiving data. If the timeout is exceeded, rsync will exit.

• --no-implied-dirs: When transferring a directory, this option prevents the creation of implied directories on the destination side that exist in the source but not explicitly specified in the transfer.

• --files-from=FILE: Read a list of source files from the specified FILE. This can be useful when you want to transfer specific files.

• --update: Skip files that are newer on the destination than the source. This is useful for incremental backups.

• --ignore-existing: Skip files that already exist on the destination. Useful when you want to avoid overwriting existing files.

• --inplace: Update files in place instead of creating temporary files and renaming them later. This can save disk space and improve speed.

• --append: Append data to files instead of replacing them if they already exist on the destination.

• --append-verify: Append data and verify it with checksums to ensure integrity.

• --backup: Make backups of files that are overwritten or deleted during the transfer. By default, a ~ is appended to the backup filename.

• --backup-dir=DIR: Specify a directory to store backup files.

• --suffix=SUFFIX: Specify a suffix to append to backup files instead of the default ~.

• --progress: Displays the progress of the transfer, including the speed and the number of bytes transferred. This is useful for monitoring long transfers and seeing how much data has been copied so far.

These options, along with others, provide additional flexibility and control over your rsync transfers, allowing you to fine-tune the synchronization process to meet your specific needs.

Examples

• Copy data to project drives: use the --no-perms option:

  rsync -av --no-perms </path/to/local/dir> user@login.daic.tudelft.nl:/tudelft.net/staff-umbrella/<project-id>
  

  This command copies files and directories from a local source to a remote destination, preserving file attributes except for permissions.

• Synchronize a local directory with a remote directory:

  rsync -avz /path/to/local/dir user@remote_host:/path/to/remote/dir
  

  This synchronizes a local directory with a remote directory, using archive mode (-a) to preserve file attributes, verbose mode (-v) for detailed output, and compression (-z) for efficient transfer.

• Synchronize a remote directory with a local directory:

  rsync -avz user@remote_host:/path/to/remote/dir /path/to/local/dir
  

  This transfers files from a remote directory to a local directory, using the same options as the previous example.

• Delete files in the destination that are not present in the source:

  rsync -av --delete /path/to/source/dir /path/to/destination/dir
  

  This synchronizes the source and destination directories and deletes files in the destination that are not in the source.

• Exclude certain files or directories during transfer:

  rsync -av --exclude='*.tmp' /path/to/source/dir /path/to/destination/dir
  

  This synchronizes the source and destination directories, excluding files with the .tmp extension.