diff --git a/atlasPerf1.png b/atlasPerf1.png new file mode 100644 index 0000000000000000000000000000000000000000..9111698714e738a4409015c2f13bb6814eb8a583 Binary files /dev/null and b/atlasPerf1.png differ diff --git a/atlasPerf2.png b/atlasPerf2.png new file mode 100644 index 0000000000000000000000000000000000000000..46064450f311e5965b6fb9fc96218c8cebd7020d Binary files /dev/null and b/atlasPerf2.png differ diff --git a/notes/atlas.md b/notes/atlas.md index 7c57ebb9a92ca66e514057dea33372dbca57194d..9eeafa6b078d36131a6bad764a4290a741043d2e 100644 --- a/notes/atlas.md +++ b/notes/atlas.md @@ -14,13 +14,13 @@ EPaxos but......faster. ### Slow Path -size is only *f+1*! +size is only *f+1*! (flexible paxos) ## Recovery -Background: +Background, fast path iff: - *U<sub>Q</sub>dep = U(f)<sub>Q</sub>dep* (line 15 in protocol) + *U<sub>Q</sub>dep = U(f)<sub>Q</sub>dep* (line 15 in protocol)  @@ -30,11 +30,13 @@ after coordinator and one other die, but how to tell whether the fast path was to be taken? How to distinguish 2a from this version: -- "2" didn't report "c", so we should not take fast path +- "2" didn't report "c", so fast path should not be taken - assume (1) and (4) die +  -Come back to this. +Slow path quorum is *f+1* = 3, *but all f+1 need to reply*, meaning +2,3,5 have to respond, and get a *D* that does not include *c*. @@ -60,8 +62,15 @@ Recovery states:  -### When do they die? -- if coordinator dies after sending a commit that is received elsewhere +## Performance + + +Note that Epaxos w/ *f=1* also always takes the fast path, though they +don't mention this. + + +Apples to oranges here a bit. Epaxos fault tolerance increasing w/ +more sites, but Atlas not. ## Issues diff --git a/notes/atlasRecovery2.png b/notes/atlasRecovery2.png new file mode 100644 index 0000000000000000000000000000000000000000..3dd15a76fe6913c68ae3e59aeb3bf9e141012155 Binary files /dev/null and b/notes/atlasRecovery2.png differ diff --git a/notes/titan.md~ b/notes/titan.md~ new file mode 100644 index 0000000000000000000000000000000000000000..6e6226ed7de157b7c8e15f3800d24e051fa11fa1 --- /dev/null +++ b/notes/titan.md~ @@ -0,0 +1,5 @@ +# State-Machine Replication for Planet-Scale Systems (ATLAS) + +EPaxos but......faster. + +- fastpath quorum: $$\lfloor n/2 \rfloor + f$$ \ No newline at end of file