VMWare Clusters Basics, Pros, Cons, Possible RADICL implementation By: Nathan Krussel

Basics( Based on ESXi 5.0 & Vsphere 5.0) A VMWare cluster is composed of at least 2 ESX severs – There is a maximum of 32 hosts per cluster vCenter has the ability to manage multiple clusters – Maximum of 1000 hosts per vCenter Sever – 10,000 max powered on VM’s 30,000 VM’s across 10 linked vCenter instances

Basics (cont) Per Host (ESX) maximums – Max of 160 Logical Processors 25 virtual CPU’s per core 2048 Virtual CPU’s per host – 2 TB of RAM – Physical NICS (2 to 32)

Basics (cont) Cluster Maximums – 32 max hosts (DRS enabled or not) 8 max if there are over 40 VM’s per host 16 max if HA and DRS are both enabled – 3000 VM’s per cluster 512 per host – Maximum Failover rate 100%

Basics (cont) HA clusters – High Availability – Allow for failover with “Instant recovery” – Keeps cluster up and running with out losing machines until replacement server arrives – When failover occurs machine is cold booter

Basics (cont) DRS clusters – Allow for live migration (through Vmotion) – Automatic load balancing* – Keeps for “overextending” a host – No recovery based on failed server

Basics (cont) HA/DRS clusters – High availability and reliability If one host fails, VM’s are migrated accordingly – Has survivability of HA and load balancing of DRS to make a stable and responsive cluster. – Sharable resource pool – Requires no additional resources over non cluster based VI (Virtual Infrastructure)*

Pros (Based on HA/DRS Clusters) Allows for high availability, always running even in the event of a server failure – Can add/remove/replace host with out powering down the entire cluster Load balancing between all hosts and clusters* – Most users won’t notice the transition between hosts, very short pause No manual moving of VM’s neccesary

Pros (cont) Expandable infastructure Easily upgrade host hardware with out reconfiguring cluster Alerts you to failures in the cluster Automatically will shift VM’s if you put a host into maintenance mode

Cons (Based on HA/DRS Clusters) High initial investment cost Under utilized machines eat resources More noise Requires more A/C May not know exactly which host has which VM’s

RADICL Implementation This is a possible design for what could be done to RADICL Changes can be made based on funding levels and time alotted

RADICL Implementation Hosts – 12 GB+ of RAM per host – 2 CPU’s with at least 4 cores per socket – Proper cooling to prevent over heating – 4 Ethernet ports per host Cluster – 4 to 8 hosts (or more depending on need)

RADICL Implementation Miscellaneous – 2 Data stores accessible by entire cluster Fast RAID array (1+0) preferably solid state drives for active machines Templates on a slower raid array – Fast vCenter machine to handle all the creation of the VM’s – Additional program for power management of servers (optional)

References configuration-maximums.pdf configuration-maximums.pdf