Re: Tarsnap de-dup - one machine or all?
Hi Arthur, Deduplication is tied to each machine key. If you have multiple machines using the same key, then data will be deduplicated between all those systems [1]. If you have multiple machine keys, then there will be no deduplication between them. [1] If you are sharing a machine key, then the cache dir should be kept in sync between those machines: http://www.tarsnap.com/multiple-machines.html If you're just "moving" from one system to another, then you don't need to worry about keeping the cache in sync. Just copy the key and cachedir over, then test it with --dry-run and you should only see a tiny amount of new data (metadata). Cheers, - Graham On Thu, Sep 17, 2020 at 08:50:13AM +0100, Arthur Chance wrote: > Does tarsnap's de-dup work on one machine at a time or across all > machines in an account? > > The reason I ask is because I've moved a largish mail archive from one > machine to another and am unsure whether the backup on the new machine > will reuse the blocks from the old one, or whether I'll end up using > double the space. > > -- > The number of people predicting the demise of Moore's Law doubles > every 18 months.
Re: Tarsnap de-dup - one machine or all?
If you are using the same key from the previous machine then they may be de-duped as the commmand you are running has access to the previous archives. Each key is unique in a way that it should never have access to another machines data. Make sense ? On Thu, Sep 17, 2020 at 08:50:13AM +0100, Arthur Chance wrote: > Does tarsnap's de-dup work on one machine at a time or across all > machines in an account? > > The reason I ask is because I've moved a largish mail archive from one > machine to another and am unsure whether the backup on the new machine > will reuse the blocks from the old one, or whether I'll end up using > double the space. > > -- > The number of people predicting the demise of Moore's Law doubles > every 18 months. -- The fact that there's a Highway to Hell but only a Stairway to Heaven says a lot about anticipated traffic volume. signature.asc Description: PGP signature
Tarsnap de-dup - one machine or all?
Does tarsnap's de-dup work on one machine at a time or across all machines in an account? The reason I ask is because I've moved a largish mail archive from one machine to another and am unsure whether the backup on the new machine will reuse the blocks from the old one, or whether I'll end up using double the space. -- The number of people predicting the demise of Moore's Law doubles every 18 months.
