BwDataArchiv FAQs

Technology

Q: What storage technologies do you use?

A: s. https://www.rda.kit.edu/technologie.php

Q: What ist HPSS?

A: see this web site: http://www.hpss-collaboration.org

Q: How is the data secured?

A: Data is stored on magnetic tape. We use the following tape drives and technologies: LTO5 (max. 1.5 TB per cartridge), STK 10kC (max. 4 TB per cartridge) and STK 10kD (max. 8 TB per cartridge), IBM TS1140 (max. 4.5 TB per cartridge)

Features

Q: I have a suggestion for improvement. What is the award if it gets implemented?

A: You will be named on the bwDataArchiv Hall of Fame pages and are eligible for 10 years of 1 TB of free storage.

Q: How many copies of the data are made and where are they stored?

A: all data in bwDataArchiv has at least 2 copies. Data is moved to disk and from there duplicated to tape storage. There are tape libraries in two data centres in CN as well as in CS.

Q: How long will the data remain in the archive?

A: The regular retention time for files on bwDataArchiv is ten years. After this ten year period bwDataArchiv will delete your data. A warning message is send 6 months ahead to the registered mail addresses. (This is probably the biggest reason to keep at least one of the two possible mail addresses up to date). Contact us at least three months in advance to have the retention time prolonged. If you want to terminate the cooperation with bwDataArchiv or if your data is no longer needed you can delete your data yourself.

Q: How can I make sure my data did not change. Do you support checksums?

A: We store a MD5 checksum for every file. When the file is read the checksum will be build again and compared with the stored checksum. If there is no match the file will not be delivered to the user. For detailed information s. https://www.rda.kit.edu/img/FAQ-bwDataArchiv%20Data%20Protection%20%20-%20V2.pdf
Also at a more basic level on disk and on tape the data is protected with checksums.

Help

Q: I have a question. Who do I ask?

A: Support and help https://www.rda.kit.edu/english/65.php

User Registration

Q: I have registered but still cannot access the service. What is wrong?

A: Most probably the registration workflow did not finish completely. This can happen because of network errors. Go to https://bwidm.scc.kit.edu/user/index.xhtml, login with your credentials and unregister from the service. Then register again. You will receive an email after you have registered successfully.

Preparations for the usage

Checksums

Q: I want to routinely create and validate checksums of large amounts of files

A: See http://rhash.anz.ru/

Delete Data

Q: There is a directory with the name .Trashcan in my archive directory. Can you explain me its function?

A: Files deleted from the archive are put in the Trashcan. Contents of the Trashcan are not deleted by the system and therefore are accounted and to the amount of data stored. To permanently delete the data you have to open the .Trashcan and delete the files. To recover files from the Trashcan move (or rename) the files to a different location outside the Trashcan.