Data transmission

Data storage in bwDataArchiv is done via the SFTP protocol.

Important information before you archive data

bwDataArchive gives you access to large inexpensive storage by using magnetic tape as the storage medium. This has various effects:

  • When writing files to the archive, they are first stored in a hard disk cache and two redundant tape copies are created in the background. After a while, the hard disk cache is overwritten.
  • If requested data is not already in the hard disk cache, it must first be read in from tapes, which can take a while (minutes to hours in extreme cases). Your SFTP client may time out in the default configuration, since the access times are not comparable to usual storage technology. It may be possible to configure the client accordingly. If data you have requested is not immediately available, it is still being copied from tapes to hard disks - wait a few minutes and then restart the transfer.
  • Automatic tape loading and rewinding may result in slow access times, e.g. a few tens of kB/s for many small files. Retrieving a small file can take almost as long as retrieving a very large file.

We therefore strongly recommend:

Combine your data into larger data sets

e.g. as TAR, ZIP, RAR etc., before uploading. If possible, do not use files < 100 MB. We recommend file sizes in the GB range files for best performance. For more information, see the FAQs.




The protocol SFTP for data storage in bwDataArchive:

A simple way to transfer data is via SFTP. SFTP clients are available for all common operating systems:

  • Linux: sftp command, lftp (advanced), filezilla, ...
  • Windows: winscp, filezilla, ...
  • MacOS: filezilla etc.

Use the SFTP client of your choice. Please read the instructions carefully.
Do you want to transfer complete directories and continue aborted transfers? On Linux use lftp.