Re:Three years later, Mr. Moore is still letting us punt on ...
by cperciva on Friday January 27, 2012 @12:52PM
(#3519242)
Amazon is not saying it, but EBS is probably lying when doing an fsync().
Given that POSIX says "the nature of the transfer is implementation-defined" and they've defined what fsync does on their implementation: No, they're not lying.
I wouldn't say that they're being misleading, either. On a local physical disk, once fsync returns your data is safely stored unless/until the disk dies. According to the forum post you linked to, semantics on EBS are exactly the same.
fsync does not mean "has been written to spinning magnetic media".
Given that POSIX says "the nature of the transfer is implementation-defined" and they've defined what fsync does on their implementation: No, they're not lying.
I wouldn't say that they're being misleading, either. On a local physical disk, once fsync returns your data is safely stored unless/until the disk dies. According to the forum post you linked to, semantics on EBS are exactly the same.
fsync does not mean "has been written to spinning magnetic media".