Re: Packing, again

On Thursday 02 Sep 2004 04:35, Richard Waid wrote:

> Preparing local storage....
> Fetching increment....
> ReplicaError: storage has been packed since the last replica
> ( 2004-05-26 13:02:55 GMT > 2004-05-26 11:10:20 GMT )
> ReplicaError: Error from remote replica

Thats strange.... are your clocks wrong? this is saying that the master 
storage was most recently packed at 2004-05-26 13:02:55, and the most recent 
transaction on the replica is from 2004-05-26 11:10:20 GMT.

The normal solution to this problem is to keep 'enough' days of history on the 
master. when packing, dont choose "0 days".

> If it just picks up where it leaves off ... wouldn't that mean that
> you'd have to pack the replica separately anyway?

yes

> (in which case, the rsync might simply be quicker anyway).

Maybe, unless your rsync is over a low bandwidth link.

Your solution has less redundancy..... Suppose something happens to corrupt 
one old file. Your solution will copy the corrupt version onto the replica at 
the next rsync operation, and (I assume) delete the only good one.

If you only replicate using the replica tool, then all data on the replica is 
sure to be the authentic version from the first replication event after the 
data was first created.

Also beware that a naive implementation of your tar+rsync+untar solution will 
not be atomic. If something crashes half way through your untar operation 
then your replica will not be self-consistent. If you have scripts that 
defend against this type of problem then I would be keen to include them in 
the DirectoryStorage distribution.



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