Update on NCSA's mass storage system

by Michelle Butler and Katherine Caponi

NCSA has begun a long road of mass storage system upgrades this year that are scheduled to continue into the next calendar year, creating an impressive data storage and data management infrustructure.

UniTree
UniTree, the mass storage system available to all NCSA users for permanent storage, had a change in size and system connection for the disk cache in September of this year.

• UniTree changed not only to a newer high-performance RAID system, but to a faster standard protocol, doubling the performance for its disk to switch-based fiberchannel.
• At this same time, the disk cache size was tripled in size from 2 terabytes (TB) to 6TB.

Interface and networking changes
Following the decommissioning of the HIPPI local area network in August, four more Gigabit Ethernet (GigE) interfaces were added to UniTree to compensate, and four more will be added around November, bringing the total to 10.

Transfer rates
With a faster disk cache and increasing network interfaces the process of transferring data from the disks to tape must also be faster. Along with 17 other tape drives, UniTree was previously using 6 LTO tape drives for offsite copy data storage during capability testing. It has been a rock-solid tape drive technology since March and NCSA has now more than doubled the number of IBM Ultrium LTO drives, adding 10 drives to the original 6. The tapes hold 100 gigabytes (GB) per tape and transfer at 14-20 megabytes per second (MBps).

Upcoming changes
Look for more changes to the systeme very near future.

• The IBM 3590 tape drives and STK 9840 drives have been retired. All the data on those tapes will be rewritten to IBM LTO Ultrium tapes within the next year.
• The STK Powderhorn tape library will be deinstalled.
• An additional disk cache machine for a new distributed UniTree system will be added. The new disk cache machine will double the mass storage performance from 250MB/s to 500MB/s aggregate throughput with an additional 6TB of diskcache.
• In January, NCSA plans to add an additional robot arm to the Advanced Digital Information Corporation (ADIC) library to increase the performance of the library. In the spring, a new section of 5760 slots will also be added to the library to bring the capacity to 3.2 petabytes (PB).
• NCSA also plans to add 20 IBM Ultrium LTO2 drives to the ADIC library in January. LTO2 is being released this fall from IBM. The performance is expected to increase to 30MBps with a tape capacity of 200GB per tape.