SDSC Thread Graphic Issue 5, April 2006

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User Services Director:
Anke Kamrath

Subhashini Sivagnanam

Graphics Designer:
Diana Diehl

Application Designer:
Fariba Fana

Storage expansion update

Storage expansion - Addition of new silos

—Layton Chen

Click to see larger silo cells image The Production System Division at SDSC worked with StorageTek engineers to add a new Automated Cartridge System silo to the Mass Storage System (MSS). This increases the number of MSS silos at SDSC to six.

Click to see larger silo floor image The new silo has a combined data storage capacity of 3,000 terabytes with the new generation tape drives and the super density tapes (500 GB/cartridge). With the new silo and media, SDSC's storage capacity has increased to more than 18 petabytes (PBs). The silo and the new drives provide faster access to data and allows HPSS and SAM-QFS to migrate existing data to a newer and more reliable storage media with increased capacity.

Click to see larger silo robot image Thirty-two new tape drives will be attached to the new silo in April, 2006. The data rate (native/compressed) of the new tape drive will be up to 80/180MB/sec. The new silo will hold up to 6,000 tape cartridges; each cartridge will in turn hold up to 500 gigabytes of data (native) and 1.6 terabytes compressed data (typical).

Click to see larger silo wall image When a user requests data from the MSS, a robot inside a silo mounts a cartridge and the data is accessed by one of SDSC's high-performance computers. A robot can mount 350 cassettes per hour. (On average, MSS file retrieval from a silo takes one or two minutes. This includes mounting the cartridge, positioning the reader to where the data resides on tape, and transferring the data.)

Layton Chen is reachable via e-mail at

Did you know ..?

SDSC is using quotas on GPFS on DataStar to control the use of disk space.
When you have exceeded the quota limits, using the default editor "vi" may destroy the file you are editing. Use the alternate editor "vim" in /usr/local/bin on DataStar. Vim provides a warning if the file cannot be saved due to disk quotas exceeded and will not modify the existing file. - Eva Hocks