For ESXi disks provisioned by XtremIO, the recommended disk format is ‘Eager Zeroed Thick’. This format is preferred because it allocates all the space required for the disk at the time of creation and zeroes out any previous data on the physical media. Compared to other formats, ‘Eager Zeroed Thick’ provides better performance due to the pre-zeroing of the disk space, which helps in avoiding any latency that might occur during write operations as there is no need to zero out blocks before writing new data.

References:

While the specific Dell XtremIO Design document was not available, the general best practice for high-performance storage solutions like XtremIO is to use ‘Eager Zeroed Thick’ provisioning for VMs running on VMware ESXi to ensure optimal performance1.

Additional information on disk provisioning and best practices can be found in VMware’s official documentation and Dell EMC’s storage configuration guides2.

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