Performance Measurements of Tertiary Storage Devices

Abstract

In spite of the rapid decrease in magnetic disk prices, tertiary storage (i.e., removable media in a robotic storage library) is becoming in-creasingly popular. The fact that so much data can be stored encourages applications that use ever more massive data sets. Appli-cation drivers include multimedia databases, data warehouses, scientific databases, and dig-ital libraries and archives. The database re-search community has responded with investi-gations into systems integration, performance modeling, and performance optimization. Tertiary storage systems present special chal-lenges because of their unusual performance characteristics. Access latencies can range into minutes even on unloaded systems, but transfer rates can be very high. Tertiary storage is implemented with a wide array of technologies, each with its own performance quirks. However, little detailed performance information about tertiary storage devices has been published. In this paper we present de-tailed measurements of several tape drives and robotic storage libraries. The tape drives we measure include the DLT 4000, DLT 7000, Ampex 310, IBM 3590, 4mm DAT, and the Sony DTF drive. This mixture of equipment includes high and low performance drives, ser-pentine and helical scan drives, and cartridge