For the 6 ^th time since the IRIS Data Management Center began operation in 1988, we have upgraded and replaced the primary, Tier-1 data storage hardware. The reason for this frequency of upgrades is to match increased demand for data with the latest cost-efficiencies of state of the art data storage systems. The process of doing a migration is complex, as we perform a comprehensive audit of all waveform data and ensure that the Oracle database holdings are in sync, and affords us the opportunity to analyze all historical holdings in one pass.

Migrating to New Technologies – The Mass Storage Timeline

An important business rule in the life-cycle of data in the IRIS perpetual archive model is that all holdings get migrated to new technology on average of every four years. It should be noted that we stopped using tape for near-line storage in 2009, ending the cycle of tape-based storage almost completely for the first time in the history of the DMC.

The current equipment was installed in August 2012, and the transcription from the old media to the new took only 6 days, compared with 6 months in the earlier days when tape-based robotic storage was utilized.

We are now operating on SAN Hitachi Unified Storage NAS 3090 platform with 256Tb of usable disk. The 3Tb drives can be hot-added, and is running RAID 6 (8×2) with no performance penalty for reads.