When choosing a storage controller, consider both your business’s storage and performance demands and needs as well as your budget:
- If you are configuring external storage enclosures with high-performance SAS hard drives and application-accelerating solid-state drives, consider the H840 for your Hardware RAID requirements or the 12Gbps SAS Host Bus Adapter to present disks in “Pass-Thru” mode to your application.
- If you are implementing hybrid server platforms based on solid-state storage for unsurpassed performance and enterprise-class reliability, our H740P and H745 are very good choices.
- If you are a small- to medium-business owner looking for file, web, and email servers at affordable prices and low-power consumption, our entry hardware RAID PERC H330 or H345 may be the right controller for you.
When choosing a RAID controller, there are a few critical hardware features that affect performance to keep in mind:
- Controller Cache – There are two types of cache on our high performance controllers – Write Cache & Read Cache.
- Write Cache can be configured in “Write Back” or “Write Through” modes. Write Back is the default setting and is specifically used for Hard Disk drive configurations. Write Back enables write I/O to complete more quickly providing better overall disk performance. With “Write Through” mode, the architectures of our low latency, high performance flash based SAS/SATA Solid State Disks are optimized for best performance.
- Read Cache can be configured to “Read Ahead” and “No Read Ahead”. HDDs are the main benefactor of Read Ahead and provides slightly better read performance.
- FastPath™ feature enables the use of the second core on our RAID-On-Chip (ROC) Processor to accelerate write-through I/O, which enhances SSD performance
Note: For parity-based RAID (RAID5, RAID6, RAID50, or RAID60) it is essential for performance workloads to have controller cache present. Controllers with write cache are able to buffer large amounts of write I/O and have a hardware XOR engine for calculating parity. Controllers without cache such as the H330 must “Write Through” I/O directly to disk which hampers and slows overall I/O performance dramatically. While RAID5/50 is supported on the H330, the performance is considerably lower and similar to software RAID performance. We discontinued parity RAID (RAID5/50) support on our H345 controller.
For best performance with RAID5/6/50/60, Dell strongly recommends a RAID controller with controller cache and hardware XOR engine such as the H730P, H740P, H745 or the H840.