Hello everyone, recently I was part of Oracle ZFS storage Pool design discussion, mostly focused on data profile types and Oracle best practices. Oracle recommend Mirrored data profile for many ZFS storage used cases including RMAN traditional backup and image backups for best performance and availability. I strongly recommend using mirrored pool production systems. Additionally, you can use double parity or triple parity, wide stripes for non-production systems if performance is not a major concern. Believing picture say a thousand words, please see below chart representing availability, performance and capacity detail of a 70 GB storage pool. As you see from below chart Stripe data profile will provide you the most capacity without providing availability which can lead to a data loss. Additionally, you can see Mirrored data profile provide you both performance and availability.
Please see below detail description of all available data profiles:
Double parity: Each array stripe contains two parity disks, yielding high availability while increasing capacity over mirrored configurations. Double parity striping is recommended for workloads requiring little or no random access, such as backup/restore.
Mirrored: Duplicate copies of data yield fast and reliable storage by dividing access and redundancy evenly between two sets of disks. Mirroring is intended for workloads favoring high performance and availability over capacity, such as databases. When storage space is ample, consider triple mirroring for increased throughput and data protection at the cost of one-third total capacity.
Single parity, narrow stripes: Each narrow stripe assigns one parity disk for each set of three data disks, offering better random read performance than double parity stripes and larger capacity than mirrored configurations. Narrow stripes can be effective for configurations that are neither heavily random nor heavily sequential as it offers a compromise between the two access patterns.
Striped: Data is distributed evenly across all disks without redundancy, maximizing performance and capacity, but providing no protection from disk failure whatsoever. Striping is recommended only for workloads in which data loss is an acceptable tradeoff for marginal gains in throughput and storage space.
Triple mirrored: Three redundant copies of data yield a very fast and highly reliable storage system. Triple mirroring is recommended for workloads requiring both maximum performance and availability, such as critical databases. Compared to standard mirroring, triple mirrored storage offers increased throughput and an added level of protection against disk failure at the expense of capacity.
Triple parity, wide stripes : Each wide stripe has three disks for parity and allocates more data disks to maximize capacity. Triple parity is not generally recommended due to its limiting factor on I/O operations and low random access performance, however these effects can be mitigated with cache.