smueller1234
Joined 10 years ago
Joined 10 years ago
Additionally, they can use telescopes pointed at the atmosphere, using the atmosphere as a calorimeter, basically. The primary signal those telescopes look for is fluorescence, but when the direction of travel points at the telescope, cherenkov light far outstrips it in brightness, so it has to be included in the event reconstruction.
Most prominent contemporary example is the Pierre Auger Observatory https://auger.org
The Pierre Auger Observatory certainly is a large collaboration for the astroparticle physics domain though. It's a big international collaboration.
Quick anecdote: my name (S Mueller) is not on that paper's author list because we had a rule that you had to be in the collaboration for a year before getting authorship. You stayed on for a year after leaving. Very reasonable! At the time I was nonetheless a bit bummed about missing out on the big Science paper. I guess I'm on the retraction though ;)
It was a fascinating experience as a junior member to follow the collaboration internal conversation and investigation on this, because a lot of extremely principled scientists were clearly deeply worried about losing their hard earned reputation. In the end, I am convinced that we were simply unlucky.
https://cloud.google.com/blog/products/storage-data-transfer...
https://cloud.google.com/blog/products/storage-data-transfer...
Facebook's published content on Tectonic is quite good and I think it's well more recent than 2010-14.
(Current Google employee, just pointing to public content, hope that's helpful.)
They really did not appreciate the debugging experience, but maybe that's improved in 15 years. :)
It's actually a lot less user-facing per disk IO capacity that you will be able to "sell" in a large distributed storage system. There's constant maintenance churn to keep data available: - local hardware failure - planned larger scale maintenance - transient, unplanned larger scale failures (etc)
In general, you can fall back to using reconstruction from the erasure codes for serving during degradation. But that's a) enormously expensive in IO and CPU and b) you carry higher availability and/or durability risk because you lost redundancy.
Additionally, it may make sense to rebalance where data lives for optimal read throughput (and other performance reasons).
So in practice, there's constant rebalancing going on in a sophisticated distributed storage system that takes a good chunk of your HDD IOPS.
This + garbage collection also makes tape really unattractive for all but very static archives.
On the other hand, if you've been building your applications against expectations of different semantics (like POSIX), retrofitting this into your existing application is really hard, and potentially awkward. This is (IMO) why there hasn't been an overtly Colossus based Google Cloud offering previously. (Though it's well publicized that both Persistent Disk and GCS use Colossus in their implementation.)
One of the reasons why it would be extremely hard to just set up or build CFS elsewhere or on a different abstraction level is that while it may look quite achievable to implement the high level architecture, there is vast complexity in the practical implementation side. The tremendous user isolation it affords for an MT system, the resilience it has against various types of failures and high throughput planned maintenance, the specialization it and its dependencies have to use specific hardware optimally.
(I work on Google storage part time, I am not a Colossus developer.)
I don't know that it took "AI branding" to convince anybody. I think these workloads potentially enabled additional demand/market for such a product that may not have been there before.
One of the challenges with exposing native Colossus was always that it's just different enough from how people elsewhere are used to use Storage that there was a lot of uncertainty about the addressable market of a "native" Colossus offering. It's not a POSIX file system. Some of the specific differences (eg. no random writes) are part of what makes Colossus powerful and performant on HDDs, but it means you have to write your application to work well within its constraints. Google has been doing that for a long time. If you haven't, even if it's an amazing product, is it worth rewriting your applications or middleware?
Rapid Storage basically addresses this by adding the object store API on top if it (TIL from this thread that there's a lower abstraction client in the works as well).
Anyway, the team behind this is awesome. Awesome tech, awesome people. Seeing this launched at Next and seeing some appreciation on HN makes me very grateful.
This is Google + Thales doing the 3rd party operator model, with the operator being a subsidiary of Thales and not Google.
(NB: I work for Google in the EU.)
The defense was only briefly about the actual thesis, then switched over to whatever research interest the committee members had, and they'd drill into their pet subjects. This was in physics, hardly politics forward normally, and at a very well respected university.