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Cutting Software Development Time

Local Disk Requirement

Rational ClearCase "Version Object Base" (VOB) and developer workspace (VIEWS) repositories reside on a local disk due to the frequency and disk intensity of the application. The FlashDisk OpenRAID disk array, containing up to 12 disk drives, looks like just one very large local disk to the server and all applications, including Rational ClearCase that happens to run very fast. Although FlashDisk OpenRAID offers both Storage Area Network (SAN) and Network Attached Storage (NAS) capabilities, for Rational ClearCase applications it is directly attached via SCSI bus or point-to-point fibre channel interfaces and thus is a local device as required.

Disk Intense: "Merge" and "Build"

Two key functions of Rational ClearCase are the "merge" and "build" features. Both are especially disk intense and create excessive demands on ordinary disk systems. The merge function updates library entries and links new modules with existing modules, maintains directories, merges physical text with existing text and coordinates versions across all existing modules to update versions directories. A system build requires versioning of all modules in the library, compiling many or all the source modules into object code, inserting all the resulting object modules in the library, linking all the modules with existing libraries to create executables and logging the final build in the version library. All of this activity, while completely automated, is exceptionally disk intense. It is not unusual for builds to take hours to complete for moderately large projects.

Merge and build activities are always on a project's "critical path" because no further progress can be made on the project until they are completed. Thus, faster merge and build times translate directly into earlier project completion. In tests performed by Rational Software using FlashDisk OpenRAID, sample merges and builds were demonstrated to run two to 2.5 times faster - cutting 50% to 60% from the time needed to perform these tasks just by moving the Version Object Base (VOB) from local, internal disks to the local, external FlashDisk OpenRAID disk array. The benchmark results are outlined in the charts below:

FlashDisk OpenRAID
Runs Merge 2.5 Times Faster

A sample "merge" into a 2,500 module library cut the 165 second merge to just 65 seconds by running the process at more than 2.5 times the speed by moving the "Version Object Base" (VOB) to the FlashDisk OpenRAID disk array. Merge is a frequently used function and this timesaving is multiplied by the large number of merges done by each and every developer on a daily basis throughout the life cycle of the project.

FlashDisk OpenRAID
Doubles Speed of System Build

Benchmark tests on a sample build of 2,500 modules shows that the time was reduced from 315 to 155 seconds on FlashDisk OpenRAID. This time represents over 50% timesavings by running the build at over twice the speed. Larger builds are even more disk intense than this relatively simple build and will benefit even more from the faster storage platform.

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