backup / copy a vm while it is running?

Discussion in 'General Questions' started by HC_3, Nov 19, 2021.

  1. HC_3

    HC_3 Kilo Poster

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    i would like to back up my windows vm to an external hard drive. since it is large (200 gb) it takes a very long time (24 hours is displayed) to copy it.

    but i need to work with the computer and the vm. is there a way to backup (copy) the vm to an external hard drive while it is running?

    i look forward to your advice!
     
  2. DebasmitaM@Parallels

    DebasmitaM@Parallels Staff Member

    Messages:
    1,148
    Hello, please follow the steps mentioned in https://kb.parallels.com/4859 for taking back up of your virtual machine. Thanks, Parallels Team.
     
  3. HC_3

    HC_3 Kilo Poster

    Messages:
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    thank you very much for your advice, @DebasmitaM.
    >is there a way to backup (copy) the vm to an external hard drive while it is running?
     
  4. GampaA@Parallels

    GampaA@Parallels Staff Member

    Messages:
    437
    Hello @HC_3 , please follow the KB article https://kb.parallels.com/en/4859 to Backup Vm. Thanks, Parallels Team.
     
  5. HC_3

    HC_3 Kilo Poster

    Messages:
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    thank you, @GampaA@Parallels but you only referred to the same article that @DebasmitaM@Parallels has already mentioned - without somehow addressing my question:

    my question is about saving / copying an OPEN vm that is being worked with. is that possible?

    or is there any point in copying it to the mac internal ssd first (because that's faster than from internal ssd to external hdd) and then copying that copy (which is not being worked with) to the external hard drive.

    and is there a way to interrupt the copy/backup process and resume it later?
     
  6. Mark Fine

    Mark Fine Kilo Poster

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    479
    I would recommend you don't try to backup an open VM, exactly for the reasons you think it might not be a good idea.

    If it takes 24hrs to backup a 200GB file it sounds like you're trying to use a USB 2.0 external disk. A better solution would be to upgrade your backup disk to USB 3.0 or better, where 200GB easily copies in about an hour.
     
  7. HC_3

    HC_3 Kilo Poster

    Messages:
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    thank you for your advice, @Mark Fine ...

    ... and for your idea about the usb version. however, the docking station as well as the usb hub and the hard drive are usb 3.

    to be sure, also that the speed "gets through" to the hard drive: is there a way to read this out somewhere?
     
  8. Mark Fine

    Mark Fine Kilo Poster

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    479
    Something's not right then. My Win11 VM is a little under 100MB and copies in ~10'. Am using a 7200rpm WD Blue harddisk and a USB 3.0 enclosure/cable.
    I use iStat which shows disk transfer speed, which I believe is generally ~180MBps on average.
     
  9. HC_3

    HC_3 Kilo Poster

    Messages:
    113
    you are right! i have measured the connection with my seagate onetouch:

    2 mb/sec write (and 124 mb/sec read) - but that was not the hard disk. it manages 73 mb/sec write (and 133 mb/sec read).
    but it was the (encrypted) image on the hard disk that made it so slow. it had the .dmg format.

    now i tried the .sparsebundle format: 64 mb/sec write (and 114 mb/sec read).

    great - thanks a lot for your advice, @Mark Fine !
     
  10. Mark Fine

    Mark Fine Kilo Poster

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    479
    No worries. I hadn't figured on encryption/compression, because I don't really bother with it. One bad byte and the disk gets corrupted. Not worth the risk. I learned the hard way after finding out I had an enclosure with an disk interface that went bad.
     

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