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I'm setting up ESXi 3.5 on an old server, and I'm not able to launch any of the VM's that I've created (Admission check failed for memory resource). The Resource Allocation tab for the host says that Memory Reservation and Memory Unreserved are both only 48 mb (despite the machine having 1.5 gb). I've tried restricting the host to using only 512 mb, but I must not be implementing that correctly because the Reservation amount never changes. The summary tab says that only 376 mb are being used. Am I missing something, or going about this in the wrong way?

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1.5GB is very small for a box running ESXi. Perhaps it is time to add more? – Zoredache Oct 10 '11 at 18:23

Even the 1,5Gb is too low, but for testing purposes you can work with 3.5 with that memory. But you need to restrict the memory on the VMs.

But you should not use any reservations on hosts.

Regarding the issue when trying to power up he VM, try to change the reservation on the VM itself.

Check here:

Hope this can help

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