RSync destination way bigger than source

  • Hi all,

    Been struggling with this for months, can't seem to find any helpful information about this and have finally admitted defeat having formatted my destination drive and re-rsyncing the whole thing. As you can see from the screenshots attached my rsync destination is way larger than it's source, this is a fresh rsync from empty. What am I doing wrong?

    Screen shots attached showing disk space usage and rsysnc settings, stor0 is rsynced to stor1.



    Thanks in advance for your help :)

  • I think nothing is wrong with your setup. You have activated the "delete" option in the rsync dialog which is necessary to get the same content for source and destination.

    The difference in size may be caused by the different drive structures which are used for source (mdadm raid) and destination (single disk). Is "stor1" an external USB device? Some external USB enclosures do a 512 Byte to 4kB sector emulation when the disk is bigger than 2 TB to be compatible with older OS`s. It´s the overhead which depends on such parameters which causes the difference in size.


    In my opinion you can do nothing against it.

    OMV 3.0.99 (Gray style)
    ASRock Rack C2550D4I C0-stepping - 16GB ECC - 6x WD RED 3TB (ZFS 2x3 Striped RaidZ1)- Fractal Design Node 304

    Edited 2 times, last by cabrio_leo ().

  • I think nothing is wrong with your setup. You have activated the "delete" option in the rsync dialog which is necessary to get the same content for source and destination.

    The difference in size may be caused by the different drive structures which are used for source (mdadm raid) and destination (single disk). Is "stor1" an external USB device? Some external USB enclosures do a 512 Byte to 4kB sector emulation when the disk is bigger than 2 TB to be compatible with older OS`s. It´s the overhead which depends on such parameters which causes the difference in size.


    In my opinion you can do nothing against it.

    Thanks for the reply. "stor0" is indeed a RAID array and "stor1" is a single drive, all are internal SATA drives.

    All drives are using an EXT4 file system created by OMV so should not be set any differently from each other. It seems crazy I would lose 150GB+, also this only happens after I have rsync'd. The actual drive is slightly larger than the RAID disc when empty.

    Might be cause by links, if you do not preserve them but replace them by the actual file. Read the man page of rsync.

    Thanks, I have seen this mentioned before but I do not understand what that means. I have read through the rsync page but it all seems related to command line so I am not sure how this applies to the limited options I seem to have in OMV. Do you literally mean "links" as in a Windows shortcut sense? How would I set whatever is happening to not happen?


    EDIT: Do you mean symlinks, because the "archive" option should make that work properly as far as I am aware?

  • EDIT: Do you mean symlinks, because the "archive" option should make that work properly as far as I am aware?

    If hard links are used on the source side than the default behavior of rsync is not to preserve hard links but to copy as separate files. Therefore more space is necessary on the destination side. This could be another reason.

    Please have a look at the rsync FAQ: I ran rsync but the source and the target are not the same size?


    Try the -H option.

    OMV 3.0.99 (Gray style)
    ASRock Rack C2550D4I C0-stepping - 16GB ECC - 6x WD RED 3TB (ZFS 2x3 Striped RaidZ1)- Fractal Design Node 304

  • If hard links are used on the source side than the default behavior of rsync is not to preserve hard links but to copy as separate files. Therefore more space is necessary on the destination side. This could be another reason.

    Please have a look at the rsync FAQ: I ran rsync but the source and the target are not the same size?


    Try the -H option.

    Thanks for the tip. Unfortunately running with -H onto a blank drive gives exactly the same result, my rsync back up is 200+GB bigger than the source and is growing with each rsync even when no extra data is arrivng on the source.

    I think I will have to seek a better solution for backing up as I am not willing to lose that much space for no apparent reason :(

Participate now!

Don’t have an account yet? Register yourself now and be a part of our community!