Optical, Tape and Disks Costs and Performance
Optical performance:
Media Load Time 5 sec
Media Unload Time 3 sec
Average Seek Time 35 msec
Buffer Memory 32MB
Max Sustained Transfer Rate - Read 12 MB/s
Max Sustained Transfer Rate - Write 6 MB/s (with verification)
Optical vs. tape performance:
GB <---------------------- Hours ---------------------------->
Tape Read Tape Write Optical Read Optical Write
Time Time Time Time
100 0.2 0.2 4.6 2.3
200 0.5 0.5 9.3 4.6
300 0.7 0.7 13.9 6.9
400 0.9 0.9 18.5 9.3
500 1.2 1.2 23.1 11.6
600 1.4 1.4 27.8 13.9
700 1.6 1.6 32.4 16.2
800 1.9 1.9 37.0 18.5
900 2.1 2.1 41.7 20.8
1,000 2.3 2.3 46.3 23.1
Road map for LTO:
LTO4 (Dec 2006) - 1.6TB (2:1 compression) and data transfer rates of up to 240 MB/second, assuming2:1 compression
LTO5 (Planned) - 3.2 TB (2:1 compression) and data transfer rates of up to 360 MB/second, assuming a 2:1 compression)
LTO6 (Planned) - 6.4 TB (2:1 compression) and data transfer rates of up to 540 MB/second, assuming a 2:1 compression
The total costs of the libraries, including a full set of media, cards (in Euro unfortunately) and the cost per TB is:
Plasmon Optical Libraries Capacity Cost Per TB
24 slot, 1.44TB optical library with one 60GB UDO2 drive, single SCSI Bus 1,440 €4,900.00
24 slot, 1.44TB optical library with two 60GB UDO2 drives, single SCSI Bus 1,440 €6,800.00
32 slot, 1.92TB optical library with one 60GB UDO2 drive, single SCSI Bus 1,920 €4,600.00
32 slot, 1.92TB optical library with two 60GB UDO2 drives, single SCSI Bus 1,920 €6,000.00
80 slot, 4.80TB optical library with two 60GB UDO2 drives, single SCSI Bus 4,800 €3,800.00
174 slot, 10.5TB optical library with two 60GB UDO2 drives, single SCSI Bus 10,440 €3,200.00
238 slot, 14.3TB optical library with four 60GB UDO2 drives, single SCSI Bus 14,280 €4,200.00
238 slot, 14.3TB optical library with six 60GB UDO2 drives, single SCSI Bus 14,280 €4,600.00
238 slot, 14.3TB optical library with eight 60GB UDO2 drives, dual SCSI Bus 14,280 €5,000.00
238 slot, 14.3TB optical library with twelve 60GB UDO2 drives , dual SCSI Bus 14,280 €5,700.00
238 slot, 14.3TB optical library with twelve 60GB UDO2 drives, triple SCSI Bus 14,280 €5,800.00
438 slot, 26.3TB optical library with four 60GB UDO2 drives, single SCSI Bus 26,280 €3,200.00
438 slot, 26.3TB optical library with six 60GB UDO2 drives, single SCSI Bus 26,280 €3,400.00
438 slot, 26.3TB optical library with eight 60GB UDO2 drives, dual SCSI Bus 26,280 €3,600.00
438 slot, 26.3TB optical library with twelve 60GB UDO2 drives , dual SCSI Bus 26,280 €4,100.00
438 slot, 26.3TB optical library with twelve 60GB UDO2 drives, triple SCSI Bus 26,280 €4,100.00
638 slot, 38.3TB optical library with six 60GB UDO2 drives, single SCSI Bus 38,280 €2,900.00
638 slot, 38.3TB optical library with eight 60GB UDO2 drives, dual SCSI Bus 38,280 €3,100.00
638 slot, 38.3TB optical library with twelve 60GB UDO2 drives , dual SCSI Bus 38,280 €3,400.00
638 slot, 38.3TB optical library with twelve 60GB UDO2 drives, triple SCSI Bus 38,280 €3,400.00
The cost per TB of large scale tape libraries is less than €200, again with a full set of media, interface cards, etc.
The cost per TB of disk, including offsite realtime replication, is of the order of optical. So twice the capacity for the same price at greater speed and usability.
Optical is an answer to a question no one is asking.
Sorry for the crappy table formatting but I got tired entering TABs.