Choosing the right server storage solution can be based on a number of factors including response time metrics, service level agreements and workloads. While more traditional workloads benefit from multiple hard disk drives (HDDs) and CacheCade, highly random workloads can benefit by using a solid-state disk-based solution. Customers requiring high bandwidth and low latency serviceable solutions will also benefit from using SSDs.
 | Good: HDD/Aggregating Multiple HDD Hard drives (HDDs), while traditionally offering a good mix of low cost and superior capacity, are limited due to their rotating mechanical components to a fixed amount of random I/O (input/output) with average latency. |
 | Better: Dell PERC with CacheCade and SSD Utilizing the power of the Dell PowerEdge™ RAID Controller (PERC) attached to serial attached SCSI SSDs provides two SSD implementations to improve HDD random I/O performance. CacheCade software running on PERC creates a supplemental layer of read-only cache between the HDDs and the database application. Frequently accessed read data is identified and stored in the SSD cache. On subsequent requests, reads are serviced from cache rather than HDD, thus lowering access times and improving random I/O performance. In addition to CacheCade, SSDs can also be utilized as primary data storage to boost the performance of both read and writes while not requiring any cache warming to take effect. The entire capacity of SSD storage can be utilized and no degradation in random I/O performance will be noticed, unlike traditional hard drives.
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 | Even Better: PCIe-SSS devices PCIe-SSS devices can be used as either storage caches or very fast storage tiers. As a storage cache, they can be used to cache such things as page files. As a storage tier, they can be used to hold frequently accessed data, often referred to as hot data. Close proximity and direct connection to the processor provides an access mechanism with much lower latency, making them especially suitable for these types of uses. New generations of PCIe will provide for even greater bandwidth than what is available today and will go even further in lowering the effective access latency. |
 | Excellent: Dell PowerEdge Express Flash PCIe SSD PCIe-SSD leverages the performance benefits of PCIe-SSS, where applications require ultrahigh performance and benefit from the lowest latency and highest IO processors achievable, and support caching and primary storage usage models. The drive form-factor of the PCIe-SSD enables the serviceability that users expect, allowing use in high availability and mission-critical applications as well as drive scalability within a server or storage platform. Dell PowerEdge Express Flash benefits mostly in OLTP (Online transaction processing), OLAP (Online analytical Processing), Collaborative (SharePoint) environments and virtualization.
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