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Castor: CERN Advanced STORage Manager

castor.web.cern.ch

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Re: Castor: CERN Advanced STORage Manager

#11

Post by bfkwlfkjf »

tempay wrote: post #6

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 CASTOR is the old system that has since been replaced by the CERN Tape Array since ~2020: https://cta.web.cern.ch/cta/ This is mentioned on the page but it’s easy to miss.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: ht…

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

Re: Castor: CERN Advanced STORage Manager

#13

Post by tempay »

rzzzt wrote: post #9
tempay wrote: post #7

Earlier quoted context omitted.

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

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

Latin and Greek aren’t one of the working languages at CERN (French and English are)

Re: Castor: CERN Advanced STORage Manager

#14

Post by tempay »

bfkwlfkjf wrote: post #11
tempay wrote: post #6

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 CASTOR is the old system that has since been replaced by the CERN Tape Array since ~2020: https://cta.web.cern.ch/cta/ This is mentioned on the page but it’s easy to miss.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: ht…

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

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.

Re: Castor: CERN Advanced STORage Manager

#15

Post by sam_bristow »

bfkwlfkjf wrote: post #11
tempay wrote: post #6

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: ht…

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

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."

Re: Castor: CERN Advanced STORage Manager

#19

Post by linksnapzz »

dokyun wrote: post #17

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/

You could use tape as a backing for Venti arenas; don't know if anyone ever did so. The original Bell Labs fileserver used an MO jukebox for WORM archives, which today LTFS tape is a pretty close approximation of.

Re: Castor: CERN Advanced STORage Manager

#20

Post by linksnapzz »

Melatonic wrote: post #5

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?

If it's Oracle Tape, it's proprietary T10000-series 1/2in linear tape and associated drives, that they got when they absorbed Sun (and Sun got when they bought StorageTek). Multiple vendors made tape media for these, but they were not compatible w/ LTO tape nor the IBM 3590-series enterprise tape format.
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