Castor: CERN Advanced STORage Manager

Castor: CERN Advanced STORage Manager(castor.web.cern.ch)

39 points by naves 3 hours ago | 15 comments

tempay 1 hour ago |

I’m a little confused by this submission. CASTOR is the old system that has since been replaced by the CERN Tape Array since ~2020: https://cta.web.cern.ch/cta/

This is mentioned on the page but it’s easy to miss.

For the current status of tape storage at CERN see: https://indico.cern.ch/event/1471803/contributions/6967379/a...

For reference, most disk storage for physics data uses an in-house solution called EOS: https://eos-web.web.cern.ch/eos-web/

bfkwlfkjf 1 hour ago | |

Does tape array replace castor? Just from the names it sounds like tape array is the actual storage, and castor is an abstraction that automatically decides what's kept on disk and what's kept on tape

tempay 1 hour ago | | |

The abstraction isn’t really a thing any more. It was a nice idea but in practice it’s an operational nightmare not knowing if data is available and for how long it will be. For reference staging can take days during intense activity and you don’t want to loose performance randomly seeking around and switching between tapes.

sam_bristow 1 hour ago | | |

The linked page seems to think it does.

"As of June 29th 2020, CTA, the CERN Tape Archive, started to be operated as the successor of CASTOR and gradually replaced it."

john_strinlai 2 hours ago |

looks like the image on the right is broken, but it is supposed to be: https://cta.web.cern.ch/cta/assets/images/namespace_statisti...

(looks like this submission uses https://castor.web.cern.ch/content/home.html instead of https://castor.web.cern.ch/castor/ the second link does not have the broken image)

Melatonic 1 hour ago |

This is actually super useful for real world stuff. Thanks for this.

Tape is boring but when an intern / AI / tectonic plate accidently destroys your database setup it is a huge lifesaver

Anybody know what these fancy Oracle tapes are? Is it just their implementation of a regular standard?

tempay 1 hour ago | |

See this conference talk from last week: https://indico.cern.ch/event/1471803/contributions/6967379/

There isn’t a recording but slides at linked from that page.

perlgeek 1 hour ago |

"Castor" was the name of a storage system used for transporting nuclear waste in Germany. There were quite a few protests against shipping nuclear waste through the country.

Wouldn't have been my choice for a software project :-)

tempay 1 hour ago | |

It’s also French for Beaver which is more likely the origin of the name.

rzzzt 1 hour ago | | |

It's also Latin and Greek for beaver which is more likely the origin of the name.

dokyun 51 minutes ago |

Wonder how this compares to Venti[1]. It looks a lot more complicated (not really a good thing).

[1]: https://doc.cat-v.org/plan_9/4th_edition/papers/venti/

boznz 1 hour ago |

The various CERN web pages such as this were a treasure trove of information when I was working on my last novel. I actually included a few paragraphs on Castor thinking of using it as a side-plot, but my editor cut the plot out along with a few other technical niceties. Sigh!

mrlonglong 1 hour ago |

They now have over an exabyte worth of data on tapes.