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15.17 High-End Tape Placement on System i
The current high-end tape drives (ULTRIUM-2 / ULTRIUM-3 and 3592-J / 3592-E) need to be placed
carefully on the System i buses and HSLs in order to avoid bottlenecking. The following rules-of thumb
will help optimize performance in a large-file save environment, and help position the customer for future
growth in tape activity:
vLimit the number of drives per fibre tape adapter as follows:
y For ULTRIUM-2
, 3592-J, and slower drives, two drives can share a fc 5704 or fc 5761 fibre tape adapter.
If running on a 2 GByte loop, a 3rd drive can share a fc 5761 fibre tape adapter
y For ULTRIUM-3 and TS1120 (3592-E) drives, each drive should be on a separate fibre tape adapter
vPlace the fc 5704 or fc 5761 in a 64-bit slot on a “fast bus” as follows:
y PCI-X
In a 5094/5294 tower use slot C08 or C09.
In a 5088/0588 tower use slot C08 or C09. You may need to purchase RPQ #847204 to allow the tower
to connect with RIO-G performance
In an 0595 or 5095 or 5790 expansion unit, use any valid slot
y PCI
In a 5074/5079/5078 tower, use slot C02, C03 or C04
y Note
“Ensure the fc 5761 is supported on your CPU type”
vPut one fc 5704 or fc 5761 per tower initially. On loops running at 2 GByte speeds, a second fc 5704 card can be
added according to the locations recommended above if needed.
vSpread tape fibre cards across as many HSL’s as possible, with maximums as follow
y On Loops running at 1 GByte (e.g. all loops on 8xx systems, or loops with HSL-1 towers )
Maximum of two drives per HSL loop
y On Loops running at 2 GByte (eg loops with all HSL-2 / RIO-G towers on system i systems)
Maximum of six ULTRIUM-2 or 3592-J drives per RIO-G loop.
Maximum of four ULTRIUM-3 drives or TS1120 (3592-E) drives per RIO-G loop using the fc
5704 IOA.
Maximum of two TS1120 (3592-E) drives per RIO-G loop using the
fc 5761 IOA
vIf Gbit Ethernet cards are present on the system and will be running during the backups, then treat them as though
they were ULTRIUM-3 or TS1120 (3592-E) tape drives when designing the card and HSL placement using the
rules above since they can command similar bandwidth
The rules above assume that the customer is running a large-file workload and that all tape drives are active
simultaneously. If your customer is running a user-mix tape workload or the high load cards are not running
simultaneously, then it may be possible to put more gear on the bus/HSL than shown. There may also be certain
card layouts that will allow more drives per bus/tower/HSL, but these need to be reviewed individually.
IBM i 6.1 Performance Capabilities Reference - January/April 2008
© Copyright IBM Corp. 2008 Chapter 15. Save/Restore Performance 262