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Installing Cisco Unified Communications Manager 8 on ESXi

Having problems getting CUCM 8 installed on a VM running on ESXi? So did I.

Critical Error
Validation error on HSSI mode:
VMWare Validation Failure:
Unable to validate VMWare based server disk settings.
Please check SCSI disks are at least 72GB in size and are located at 0:0 (and 0:1 in a two disk config) in machine settings.

I ran into an issue when installing CUCM 8.0.2 on a VM running on ESXi 4.1. The installer complained that it needed at least 72GB of hard-drive space. As I hadn’t read the hardware-requirements for the CUCM, I spent much of my time testing out different HDD-settings on the VM. At first I thought that it didn’t like the ESXi’s thin-provisioning, but after a while, I found out that the issue was with other settings on the VM ? specifically how many CPU’s and how much RAM it needs. It’s also recommended that you choose the OS that is as close to CUCM as possible.

So, without further ado, here’s the settings you’ll need;

  • CPUs: >=2
  • Memory: >=2GB
  • Hard disk: >=73GB (you can turn on Thin-provisioning if you want)
  • Guest Operating System: Linux -> Red Hat Enterprise Linux 4 (32-bit)

Keep in mind that this is minimum, and that you can’t set them lower after the install is done, as CUCM does the same check every time it boots.


  1. havard havard

    But what if you dont have ESXi installed, b?cause the CD-ROM drive is?nt supported..??

    • jocke jocke

      You’d have to get one that’s supported, I guess.

      </captain obvious>

      • havard havard

        bla bal alb abl lab lba

  2. lima lima

    It works! Thank you very much!

  3. Sorin Sorin

    Thanks, it helped me installing CUC 8.0.2!

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