[CentOS] [rsync -avz] total size/disk usage difference between source and destination

Rubin rubin at xs4all.nl
Mon Nov 3 09:13:32 UTC 2008


For what it's worth, I always specify my source and target paths as
absolute, ending in a slash (/). This has saved me from sneaky mistakes
many a time. Next to that, I don't know if your target filesystem is
supposed to be an exact copy of the source, but you did not specify
--delete which results in rsync not touching any files in the target
filesystem that do not match files in the source (ie. file foo exists in
target and stays there. with --delete it would be removed). I would
secify a sync between an target and source filesystem as follows:

rsync -avPH --delete /sourcefs/directoryA/ /targetfs/directoryA/

I've seen differences in fs sizes when the blocksize or type of
filesystem differ from one-another. Always wondered what the exact
underlying reason for it was (ie. I don't have a more exact answer ;-)

Kind regards,


Les Mikesell wrote:
> John R Pierce wrote:
>> Sven wrote:
>>> Hi folks
>>> We migrated storage from local disk to SAN with:
>>> # rsync -avz /mnt/lvol00045/* /lvol00045
>>> Why there is a difference in size? How to explain this? Do we have
>>> inconsistency? What we did wrong?
>>> [...]
>>> /dev/mapper/vg01-lvol00045_old
>>>                       10321208   3930336   6286016  39% /mnt/lvol00045
>>> [...]
>>> /dev/mapper/vg01-lvol00045
>>>                       10321208   3163852   6633068  33% /lvol00045
>> did rsync copy .* hidden files ?
>> do the two file systems have the same block size?
> Rsync would copy hidden files when recursing as a side effect of the -a
> option.  However, the shell is going to expand that '*' before rsync
> sees the command line and miss any hidden files in the top level
> directory.  I'd probably have done:
> cd /mnt/lvo100045
> rsync -avH . /lvo00045
> instead.  That gives rsync a directory as a starting point without
> having to remember the quirks of whether it will or won't create a
> subdirectory of that name on the target.  It also doesn't make sense to
> use -z for a local file copy and you might need -H if you have
> hardlinked files on the filesystem.

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