JBOD, at the logical level combines physical disk drives into one larger drive. This comes in handy when dealing with an assortment of drives. Where RAID configuration combines drives at the limit of the smallest disk, JBOD does not.

Starting with the Reader tests, IOZone places a file on the system measures the performance of reading that file.

Next, the Re-Reader test measures the system’s caching ability. While it is typical that Re-Reader results are significantly higher than those reported in the Reader test as the test measures reading performance of a file that was previously read, the effects are insignificant with larger file sizes. If we attempted this with files in the few hundred KB mark, we would see a larger jump.

The peak read speed with JBOD hits the low 50′s. The average considering all file sizes and record sizes is 31MB/s.

The Writer test measures performance of writing a new file to the system.

The throughput of writing is 32MB/s, a touch faster than reading which is fairly remarkable. With Re-Writer the cache significantly increases the performance to an average of 70MB/s. We peak as high as 217MB/s with Re-Writer and only 93MB/s with Writer.

When writing a previously written file, the overhead required to process where data will be stored on a specific storage media is already determined; the system in a sense is required to do less, thus accounting for the vast improvement in performance.

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