The Dell EqualLogic PS5000 is a robust 16-disk system, and choosing the correct RAID configuration is crucial to optimizing performance and protecting data integrity. According to Dell’s official guidance, certain RAID configurations are better suited for specific workloads and disk types.
Selecting the Appropriate RAID Configuration
When utilizing the PS5000 with 2TB drives, it is essential to consider the workload characteristics and existing infrastructure to determine the most suitable RAID policy. Dell’s documentation emphasizes the importance of aligning RAID selection with best practices to ensure both performance and data protection:
- RAID50: Not recommended for 7.2K RPM drives larger than 1TB, especially when handling business-critical data. The potential risk of data loss due to drive failures, combined with recovery times, makes this configuration less favorable for such environments.
- RAID5: Should be avoided entirely for business-critical applications due to its lower redundancy and increased risk of data loss.
- RAID10: Highly recommended for database workloads due to its balance of performance and redundancy. However, it must be ensured that there is sufficient usable capacity to accommodate the size of the virtual machines (VMs) being supported.
Understanding Performance and Capacity Needs
Before finalizing the RAID configuration, it is beneficial to analyze current storage metrics, such as read/write ratios, average and peak IOPS, and total capacity requirements. If the virtualized environments and databases are already operational on another storage platform, leveraging this data to inform RAID choice is advisable.
Considerations for Specific RAID Levels
Each RAID level presents distinct advantages and trade-offs:
- RAID6: Generates poor performance in write-intensive environments. It may only be suitable if read operations dominate, potentially achieving up to 1500 IOPS with 100% reads on a 16-drive setup (assuming one hot spare and 8K random I/O). However, incorporating even a modest proportion of writes (e.g., 30%) can degrade performance to below 600 IOPS.
The PS5000 allows configuring one RAID policy per member or enclosure, and different RAID types require deploying multiple members/arrays, organized into discrete storage pools. This flexibility can be leveraged to optimize for various workloads within an IT environment.
Further Resources
For a comprehensive understanding and additional guidance, refer to the Dell EqualLogic documentation on RAID policies and system configuration best practices.
