Hey there! In this post we will find about the Availability features that were introduced with vSphere 6. Availability has always been an important characteristic of virtual systems and vSphere has provided many enhancements to this with the new version.
With version 6, Fault Tolerance is now supported for VMs with 4vCPU and 64GB Memory. FT now uses FastCheckpointing which copies active memory pages from primary to secondary vm continiously over the FT logging network. For this reason, FT on version 6 recommends a 10Gig network for FT logging. Fastcheckpointing is a heavily modified version of xvMotion and it executes multiple checkpoints per second.
Earlier verison of FT VMs needed a guest agent to be installed on them for them to be backed up, now with the vSpshere Storage APIs Data Protection (VADP), we can use snapshot based backups enabling easier administration.
FT now creates a complete copy of the vm enabling the files of the primary and secondary to be stored on both shared as well as local storage. FT now also supports all disk formats including Thin formats. With version 6 FT can be hot configured, meaning no dowtime is needed for configuring FT on a VM.
vSphere HA now includes Virtual Machine Component Protection (VMCP) which provides enhanced protection from All Paths Down (APD) and Permanent Device Loss (PDL) conditions for blocks such as FC, iSCSI, FCoE and NFS. VMCP detects APD and PDL conditions on connected storage, generates alarms and automatically restarts VMs on working hosts. HA can now protect as many as 64 ESXi hosts and upto 6000 VMs. HA is now fully compatible with VVOLs, NIOC,IPv6, NSX and cross vCeter vMotion.
vSphere Replication Enhancements
The Recovery Point Objective (RPO) can now be set per virtual machine basis and can range from 15 min to 24 hours. Once the RPO is set and initial replication is done, all further sync is done, only the changes to the VM are replicated reducng the network bandwidth comsumption. Further to this, the data is compressed as it is sent across network untill written to storage at the destination. Compression is done using FastLZ compression libraries.
Hope this was informative. Thanks!