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Re: Multiple Replicas



--On Sunday, June 20, 2004 7:22 PM -0400 Daniel Henninger <daniel@unity.ncsu.edu> wrote:

Hi Folk!

I'm aiming to have a setup with one master, and three slaves.  I haven't
found any documentation that explains well how this works (unless I'm just
blind), just a mention that it can be done.  My main question is, how does
slurpd or the slave or whatever know what it's already seen?  Lets say
slave B goes down temporarily.  Slave A and Slave C keep on running and
receiving updates from the master.  Slave B is brought back up, but
updates occured while it was down.  Is Slave B effectively beyond trivial
repair at this point or will it simply catch up properly?  I'm coming from
a familiarity with how MySQL handles these things, so I expected that the
slave knows "I know updates as of 2004-06-14, 2:01 am" and then can
effectively go "what have I missed?" (or visa versa, slurpd can go "what
have you missed"?..  or slurpd is the one that knows the position the
slave was at)  Anyway, let me stop babbling.  Is this setup possible and
how are situations like this handled?  Thanks!

Slurpd keeps a log of what updates each slave has seen. If a slave goes down, then the entry for that slaves doesn't get updated in slurpd's log.

--Quanah


--
Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html