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I currently have a backup solution in place that uses rsync to backup all out Linux servers from remote sites, to an XFS drive in our HQ. I am now trying to rsync the folder from the XFS drive in our HQ to a ZFS drive in another office for Disaster recovery purposes.

This isn't necessarily a problem but I have noticed that the folder on ZFS is approximately 80 GB larger than the original on XFS. Does anybody know why this is happening? And perhaps how I could fix it.

XFS(HQ) = 905 GB ZFS(DR) = 983 GB

Thanks in advance.

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Is this really a problem? – ewwhite Mar 18 '13 at 15:01

It's normal to see this type of variation due to differences in metadata size.

BTW, I'd recommend two things. One, use rsync's checksum option so that it's not just comparing file timestamps as it does by default. Two, be sure you turn on compression in ZFS.

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Thanks. I did expect some change due to metadata but I guess not as much I am. Also, I will take your recommendations into consideration. – James Mar 18 '13 at 16:30
+1 for turning on compression. lzjb is one of those 'should always be on' sort of things. The amount of CPU overhead it creates is negligible compared to the speed of the disks. It'll likely transfer faster. Also, if you are turning on compression, don't forget to rewrite the dataset so the blocks are written back compressed. – RandomInsano Mar 20 '13 at 23:55

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