Many different storage systems can fall under the SDS category. Even DFS listed below falls under SDS. Software RAID could also fall under the SDS category. Two common SDS feature-rich offerings are Microsoft Storage Spaces and ZFS or ZFS on Linux (ZOL). Microsoft Storage Spaces is available in Windows Server and offers features like storage tiers, write-back cache, and parity space support for failover clusters, dual parity, and auto rebuild from storage pool free space.
Between ZFS and Microsoft Storage Spaces we find the features of ZFS the most interesting. ZFS has been around for more than a decade, it was originally developed by Sun Microsystems. ZFS is a file system, disk management system, software RAID, share management system all-in-one. ZFS is a copy on write FS. You change a file and ZFS will write a copy of that file to your disk, only after the copy is written without errors is the original file deleted. That way crashes during a write won’t corrupt the data on your disk. ZFS checksums all data and metadata which helps ZFS detect and correct errors in stored data resulting from bit rot. It will detect and correct bit rot that hard drive SMART technology often misses. ZFS has more redundancy available than even RAID 6 allows; triple parity instead of double parity. Snapshots, deduplication, compression and capacities in the exabyte range are all included.
ADVANTAGES
- Low cost
- Fast to deploy
- Massively scalable
- Can provide high reliability beyond double parity
- Not limited to capabilities of hardware controllers
- Can provide replication both locally and remotely
- Tiered storage capable
- Can snapshot data
DISADVANTAGES
- Makes no sense in small environments
- Can make data recovery complex
- Requires sophisticated data recovery and regular backups
BEST USES
- Can provide HA(high availability) in some cases
- Good where data growth will be key
- Excellent where high reliability and redundancy is needed
- Good where tiered storage is a benefit
- Good if replication is important or snapshots are needed
