2 Replies Latest reply on Oct 30, 2014 10:34 AM by wila

    Compression takes much time.

    budyonuj Novice


      I'm using VMware ESXI 5.5.0 2068190

      I'm using IBM System X Server with 2 six-cores CPU's, and 32 GB RAM.

      I have 6 VM's (Windows servers 2000,2003,2012)

      I have 2 datastores:

      1-st - RAID 5 with 5 SAS 10K RPM HDDs

      2-nd RAID 5 with 5 SAS 15K RPM HDDs

      I'm trying to use GhettoVCB to backup my VM's with the next scheme:


      I have backupstore folder on one the first datastore.

      GhettoVCB script is configured to backup VM to that folder

      I use Enable_compression=1 parameter to compress my backup. (I Know that i'll have some problems with it's uncompressing but i learned how to solve it)

      Than after VM's backup is compressed script is copying to NFS share.

      When i'm making backup of virtual machine with Thick mode HDD, with 200GB Size, and operating system Windows Server 2012, backup takes less than 5 minutes.

      But it's compression on esxi takes 96 minutes. Compressed backup size is 6 Gb

      Than i'm making backup of virtual machine with Thick mode HDD, with 300GB Size. and operation sytem Windows Server 2003 R2. Backup takes 5 minutes.

      It's compression takes: 486 Minutes!!!!!!!!!

      Compressed backups size is 47 Gb.

      But the most interesting is the next

      Virtual machine with two 34 GB HDD's. Windows server 2000. Backup Takes 6 minutes. But it's compressing takes 515 minutes.

      Can somebody advise me??

      What's the problem with it?

      I've attached log files to three vm's i've wrote upper.

      I'f somebody need any additional info about Host or VM's please ask me and i'll give it.


        • 1. Re: Compression takes much time.
          OresteCanello Lurker

          Compression normally take a lot of time. I think the problem is in reading and writing a lot of data simultaneously in the same datastore (especially if NFS and not a so high performance store...) I tried compression on a top level storage (FC SAN with SSD fast cache)  and compression was very fast, if I switch on a slower storage (a NFS mounted NAS with 4x 7.2 Sata disks) the time grows a lot!

          From vcenter performance monitor I can see the datastore latency growing up to250ms!!!, so I think it's a storage performance issue.


          For the next version I think a very good idea will be insert a new parameter for a "temp" folder, so GhettoVCB can copy uncompressed temporary images in a different datastore and avoid congestion

          • 2. Re: Compression takes much time.
            wila Guru
            User ModeratorsvExpertCommunity Warriors

            Actually the problem with compression in ghettoVCB is that you are doing this in the management console.

            The management service is severely limited in resources (and for good reasons) and can only user core 0 of the first processor on your host.

            You should not use the compression option in a production environment, only for labs as you are basically putting a lot of load on your management environment. Compressing is a CPU and memory intensive operation.


            Your VMs and management services might be hampered by all the load of the compression, the available resources in there have not been designed to be used that way.


            So while I think it is great that you can do this, you should use another machine or even a VM for the actual compression.

            You will notice that it will be a LOT more performant that way.


            hope this helps,



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