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VM Placement Rules
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Physical memory must not be oversubscribed.
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Usable RAM: Memory configuration must provide at least as many GB as the sum of all virtual
machines' vram plus additional memory for ESXi itself. At the time of this writing, additional usable
GB from ESXi Hardware Requirements are:
o
ESXi 8.0 minimum 8GB, 12GB for typical production deployments.
Storage Requirements
General
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If Cisco Calling Appliance, the storage hardware and RAID configuration are selected by default in
the appliance model (no changes are supported). For more details, see Install Guide of each
appliance.
- Cisco Unified Communications Manager and the IM and Presence Service
- Cisco Expressway Installation Guide
- Cisco Emergency Responder Administration Guide
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For Cisco General-purpose and 3rd-party General-purpose hardware, must follow:
◦ The "storage system" is defined as all hardware and software end-to-end required for the UCM virtual
machine's vdisk to be available to the application. Including but not limited to:
o
The ESXi datastore configuration.
o
One of the following:
RAID controller with local DAS disks.
Network adapter, transport network and 3rdparty SAN/NAS array.
Hyperconvergence software (AOS, HXDP, and more) and underlying hardware.
o
The entirety of the storage system must be listed as supported by the ESXi release being run,
per the beginning of this chapter.
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ESXi datastores may be provisioned with eager zero or lazy zero.
VM Placement Rules
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Maximum latency of storage system: Application requirements must be met, or the storage will be
inadequate for the application software load presented. For application symptoms that correlate
with high storage latency, Cisco may require resolving the storage latency before proceeding with
troubleshooting or resolution.
◦ Unless otherwise indicated, Cisco Collaboration applications require storage systems to have average
virtual machine operating system latency per command <= 25 ms.
o
In VMware documentation and monitoring tools like esxtop, this is also called "GAVG/cmd"
(Guest Average Latency per command), and is the response time as perceived by the guest
operating system. It is the sum of two other latency values (GAVG = KAVG + DAVG):