Deduplication and Compression for Space Efficiency
Nearline deduplication and compression per disk group level.
Space Efficiency enabled on a cluster level.
Deduplicated when de-staging from cache tier to capacity tier.
Compressed after deduplication.
Erasure Coding (RAID 5)
Sometimes RAID 5 and RAID 6 over the network is also referred as erasure coding. In this case RAID-5 requires 4 hosts at a minimum as it uses a 3+1 logic. With 4 hosts 1 can fail without data loss. This results in a significant reduction of required disk capacity. Normally a 20GB disk would require 40GB of disk capacity, but in the case of RAID-5 over the network the requirement is only ~27GB. There is another option if higher availability is desired
Erasure Coding (RAID 6)
With RAID-6 two host failures can be tolerated, similar to FTT=2 using RAID-1. In the traditional scenario for a 20GB disk the required disk capacity would be 60GB, but with RAID-6 over the network this is just 30GB. Note that the parity is distributed across all hosts and there is no dedicated parity host or anything like that. Again, this is sometimes by others referred to as erasure coding. In this case a 4+2 configuration is used, which means that 6 hosts is the minimum to be able to use this configuration.
Virtual SAN Quality of Service
Enhanced Virtual SAN Management with New Health Service
Virtual SAN – Usability & Manageability : Health Check
SNMP support, custom scripts, emails via VC alarms
Performance Monitoring – Web client integrated
Cluster wide summary of VM availability
Event based alarm triggers
Detailed Space Reporting (account for dedup etc)
Proactive rebalance from UI (Health and actions)
Alarms on performance threshold breach
Integrate performance data in support bundle
Write through read memory cache
Local to the virtual Machine
Low overhead, big impact
Reclaim Space used by memory swap
Host advanced option enables setting policy for swap to no space reservation.