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14.2.3 12X Loop Testing
A 9406-MMA 8 Way system with 96 GB of mainstore and 396 DASD in #5786 EXP24 Disk
Drawer on 3 12X loops for the system ASP were used, ASP 2 was created on a 4th 12X loop by
adding 5796 system expansion units with 571F IOAs attaching 36 4327 70 GB DASD in #5786
EXP24 Disk Drawer with RAID5 turned on. I created a virtual tape drive in ASP2 and I used a
320GB file to save to the tape drive for this test.
When I completed the testing up to 288 DASD on 8 IOAs, I moved the 12X loop to the other
12X GX adapter in the CEC and ran the test again and saw no difference in the testing between
the two loops. The 12X loop is rated for more throughput than the DASD configuration would
allow for. So the test isn’t a tell all about the 12X loops capabilities only a statement of support
to the maximum number of 571F IOAs allowed in the loop.
IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008 Chapter 14 DASD Performance 207
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Number of 571F IOAs
GB/HR
12X Loop testing from 1 571F to 8 571F IOAs with 36 DASD off each 571F