271–280 of 319 posts
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My first computer had 38911 BASIC BYTES FREE.
Luxury! My first computer (Sinclair ZX Spectrum) had 48KB RAM total, and IIRC 8KB of BASIC RAM available.
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There is a "Datacenter-aware mode": https://apple.github.io/foundationdb/configuration.html#data... Here is some discussion about linearizabilty in fdb: https://news.ycombinator.com/item?id=16884882
Without knowing exactly how reads and writes are replicated, I am skeptical. I have gone through the technical documentation and haven't found many details. For reference, I've done work in storage and consensus algorithms and I can tell you for a fact that without using a consensus algorithm for either reconfiguration or request propagation, you will have consistency violations. I would love to be proven wrong, as m…
Besides its extensive documentation, you can read its source code and run its deterministic simulation tests yourself if you are interested (it's Apache licensed). Skepticism on these points was reasonable when we originally launched it in 2012 but is getting a little silly in 2018.
CTO of YugaByte here. We firmly stand by our claims, and I wanted to explain more. From the post by Daniel: YugaByte, however, continues to claim a guarantee of consistency. I would advise people not to trust this claim. YugaByte, by virtue of its Spanner roots, will run into consistency violations when the local clock on a server suddenly jumps beyond the skew uncertainty window. >> The statement about YugaByte DB i…
Looks like you cross-posted this comment here and on my blog, so I'll also cross-post in my response. I am quite confused by your statement that YugaByte does not claim linearizability. The C of CAP is linearizability (see the original CAP theorem https://users.ece.cmu.edu/~adrian/731-sp04/readings/GL-cap.p... ). By claiming to be CP from CAP, you are claiming linearizability. CockroachDB also makes the same CP claim…
From the bailis.org link you posted:
> Linearizability is a guarantee about single operations on single objects.
The place we references "linearizability" (in the Jepsen blog and docs) are in the context of single row-key operations; I can update our docs to clarify that further.
For multi-key transactions, our docs clearly point out that we support Snapshot Isolation now and Serializable Isolation is in the roadmap.
CTO of YugaByte here. We firmly stand by our claims, and I wanted to explain more. From the post by Daniel: YugaByte, however, continues to claim a guarantee of consistency. I would advise people not to trust this claim. YugaByte, by virtue of its Spanner roots, will run into consistency violations when the local clock on a server suddenly jumps beyond the skew uncertainty window. >> The statement about YugaByte DB i…
Looks like you cross-posted this comment here and on my blog, so I'll also cross-post in my response. I am quite confused by your statement that YugaByte does not claim linearizability. The C of CAP is linearizability (see the original CAP theorem https://users.ece.cmu.edu/~adrian/731-sp04/readings/GL-cap.p... ). By claiming to be CP from CAP, you are claiming linearizability. CockroachDB also makes the same CP claim…
http://dbmsmusings.blogspot.com/2018/09/newsql-database-syst...
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> If the code is written in a distributed fashion from the start then it can be designed so it's one python/node/R process per core. That's a really glib dismissal of how hard the problem is. Python and node have pretty terrible support for building distributed systems. With Python, in practice most systems end up based on Celery, with huge long-running tasks. This configuration basically boils down to using Celery,…
Am I correct in assuming Elixir/Erlang does a much better job at this compared to Node/Python/etc., putting aside (what I understand to be) the rather big problem of their relative weakness for computation?
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http://www.supermicro.com/products/system/4U/8048/SYS-8048B-... Quad socket R1 (LGA 2011) supports Intel® Xeon® processor E7-8800 v4/v3, E7-4800 v4/v3 family (up to 24-Core) Up to 12TB DDR4 (128GB 3DS LRDIMM); 96x DIMM slots (8x memory module boards: X10QBi-MEM2) AFAIK the latest Skylake Xeons ("Scalable" - Platinum/Gold/Silver/Bronze) have regressed to 1.5TB support, see https://ark.intel.com/products/93794/Intel-Xe…
That's a previous-gen CPU system. Current is: https://www.supermicro.com/products/system/7U/7089/SYS-7089P... Server itself is might only be $25k but those 224 cores could add another $90k, so the total would be close to $400k. The previous-gen version, SYS-7088B-TR4FT (link in my comment upthread), has 192 DIMM slots, so if you don't need CPU horsepower, you cn get the lower-density modules and still have 12TB (or t…
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I'm not sure anyone would ever actually have only one machine, without a failover option, and failing over had better not bring down the whole system.
But now we're back to a distributed system
When a replica is used as a read slave, that introduces problems with (strong) consistency, that definitely starts to resemble any other distributed system.
Adding automated failover adds the need for some kind of consensus algorithm, another feature of distributed systems.
However, if failover is manual, for example, then 2 nodes can be nearly indistinguishable from 1 node, if no failover occurs.
It also strains the definition of "distributed" if both nodes are adjacent, possibly even with direct network and/or storage connections to each other.
Which brings me to my point - what the author fails to talk about is why spanner has taken the design decision they have made. He does claim scalability, but that is a very general word.
I believe the spanner decision is to avoid making a global voting, as in global across the entire world, from North America, to Asia, Europe and even as far as Australia. Such a global voting will take a lot of time - impose seconds of later on any write.
I think the author, when he talks about having a single global vote with a small window, thinks in terms of a single database, maybe two regions on the Continental USA, as apposed to spanner trying to be Geo distributed.