Experience with the UniTree mass storage system

Lawrence Berkeley Laboratory (LBL) is a beta test site for the UniTree mass storage system. Our initial configuration is based on a Sun workstation and includes 10 gigabytes (GB) of magnetic disk cache, 700 GB of Exabyte 8 mm tape storage, with two tape robots. We support a user community of 15 to 20 active users, about 250,000 files, and 33 GB of user data. The largest file stored is 1.5 GB. As of May 1992, we consider the system to be adequately stable and reliable for production use. As a beta site, we have worked on the Sun port, on the tape drivers for SunOS, and on integrating our tape robots into the UniTree software. File retrieval from tape usually takes less than five minutes. Continuing concerns are tape longevity and reliability, and improving performance to support 100 Mb FDDI.