I covered Compression, Deduplication, and Erasure Coding in the NCP Study Guide. However, there’s always more to learn!

Compression

Workloads Recommended for Compression

• Almost all

Workloads Not Ideal for Compression

• Encrypted datasets
• Already compressed datasets (for example, images, audio, or video)

Deduplication

Workloads Recommended for Deduplication

• Base images (cache)—you can manually fingerprint them using vdisk_manipulator
• P2V and V2V when using Hyper-V (ODX uses a full data copy)
• Cross-container clones (not usually recommended because single containers are preferred)

Workloads Not Ideal for Deduplication

• Anything outside the recommendations above. In most cases, compression yields the highest capacity savings and should be used instead.

Erasure Coding

EC-X pairs perfectly with inline compression; you can safely enable them together for maximum efficiency.

The savings from the erasure coding feature depends on the cluster size and coldness of the data.

Consider a 6-node cluster configured with redundancy factor 2. A strip size of 5 is possible: 4 nodes for data and 1 node for parity. Data and parity comprising the erasure coded strip leaves one node in the cluster to ensure that if a node failure occurs, a node is available for rebuild. If you use a strip of (4, 1), the overhead is 25% (1 for parity and 4 for data). Without erasure coding, the overhead is 100%.

So what savings can be attributed to EC-X?

Replication Factor of 2 (RF2) allows the utilization of about 50% of raw storage capacity. EC-X can take this utilization to 80%.

Workloads Recommended for Erasure Coding

• Write once, read many (WORM) workloads
• Backups
• Archives
• File servers
• Log servers
• Email (depending on usage)

Workloads Not Ideal for Erasure Coding

• Anything write- or overwrite-intensive
• VDI