Solid State Drives

Solid State Drives

Solid State Drives (SSDs) offer a number of advantages over traditional hard disk drives (HDDs). With no seek time or rotational delays, SSDs can deliver substantially better I/O performance than HDDs. Capable of driving tens of thousands of I/O operations per second as opposed to hundreds for HDDs, SSDs break through performance bottlenecks of I/O-bound applications. Applications that require dozens and dozens of “extra” HDDs for performance can meet their I/O performance requirements with far fewer SSDs, resulting in energy, space, and cost savings.

As IBM® i has it’s own storage manager and DB2® for i built in, the integration of SSDs on IBM i is a fairly simple task. The functions provided for management of SSDs and adjusting their impact on Applications and Database are very simple and easy to use.

To compare and contrast these methodologies see the IBM i white paper:

http://www-03.ibm.com/systems/resources/ssd_ibmi.pdf

To allow you to specify what data should be allocated on SSD, DB2 has provided the capability to specify a “media preference” as an attribute of a database table, partition, or index. It should be noted that this attribute specifies that storage allocations on SSD are preferred, but if no SSD disks are available or if the SSD disks do not have enough space left to allocate the entire object, at least some part of the object will be allocated on traditional disks. See the UNIT parameter on CRTPF and CRTLF or the media-preference clause (UNIT SSD) on the CREATE TABLE, DECLARE GLOBAL TEMPORARY TABLE, CREATE INDEX, and ALTER TABLE SQL statements.

You should consider SSDs if your I/O demands have outpaced the performance capabilities of traditional HDDs, latencies associated with spinning platters and moving arms limit the speed of HDD data access. SSDs near instantaneous data access removes this I/O bottleneck, creating a paradigm shift in I/O performance. Applications throttled by poor I/O performance can benefit greatly from SSDs.