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AlbertWT
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Enabling CBT for all ESX VMs ?

Hi,

Does enabling CBT for all of the Virtual Machine that is managed by my Virtual Center is a good idea or not supposed to be due to the CBT overhead files ?

Do I need to reboot all of the Virtual Machine once I enable the CBT option manually one by one though the vSphere Console Edit Settings for each VM ?

Your assistance and help would be greatly appreciated.

Thanks

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a_p_
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Not sure about Avamar, but I'm pretty sure it provides an option to enable CBT. Networker provides a script to enable CBT. However, IIRC there's an issue with file-level restore when you use CBT with version 7.6!?

André

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MarVista
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As known VMware acknowledges that CBT could lose track of incremental changes in the event of a power failure or hard shutdown. so its up to you and you dont need to reboot once you enable the CBT and apply it .

Hope that will help .

Yours,
Mar Vista

AlbertWT
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OK, so in this case is there any caveats that I need to consider when using this feature ?

My aim is to have a safe backup of all the production VM with smaller foot print and quicker backup window, I was thinking to enable it in all 450+ VM in my data center by using Powershell script.

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a_p_
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Which backup application do you use? Most of them provide either built in options or scripts to enable CBT?

André

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AlbertWT
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I'm using EMC Avamar 6.2 and Networker 7.6

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Disclaimer: This email was sent from my iPhone, apologize for any typographical error.

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a_p_
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Not sure about Avamar, but I'm pretty sure it provides an option to enable CBT. Networker provides a script to enable CBT. However, IIRC there's an issue with file-level restore when you use CBT with version 7.6!?

André

AlbertWT
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Thanks Andre for the reply and clarification, but aside from the vendor bug / issue, there is no data store overhead or anything significant that I must be aware when implementing this feature in the large data center environment ?

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a_p_
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CBT creates a fixed size ...-ctk.vmdk file (about 0.5MB per 10GB - see What is Changed Block Tracking in vSphere?) for each virtual disk (.vmdk) file to store the information about the changed blocks. I didn't do any performance tests, but since CBT is built into the VMkernel there's should  not be a noticeable overhead for this.

André