SCSI Jumper Help Adding New Drives 1

[adamroof]

Have a PERC4/SC single channel with 4 36GB 15K Fujitsu drives, bought 2 more drives from DELL and had to buy a 7 device 68pin U320 cable elsewhere

the drives came and are Seagate's

the two new drives wont recognize, gots ta be jumpers, i set the address or so i thought to 13 and 14, thinking the existing drives are 9 10 11 and 12

also have a tape drive, when booting it states the LSI controller is 7, tape device is 5

1. im quite new with SCSI mixn match, am i out of line to do this addition?
2. how can i confirm the current settings of the 4 drives?
3. can an ID be skipped?
4. the 2 drives by themselves would not recognize by the controller, the cable is good, works with existing 4 and boots to OS

the seagates have LSI chipsets, so do the fijuhistus.

the current 4 use the underside jumpers, the new drives have a backside jumper that sets the address.

New ---

- R 0 0 0 0 not certain on top row(isnt specified)
- R 8 4 2 1

pins as shipped were on 8-4; 2-1 both drives
i changed to 8-4;2-0 on one and 8-4; 1-0 on other (14 n 13 right?)

cant find info on existing drives.

thanks if you can shed info and my dark light.

 

[adamroof]

ok, im wacked...

tape is on onboard controller

drives are on pci PERC4/SC
controller ID7,

i think the drives are ID 0-3
would that mean i should set the two drives to 4 N 5?

so i should pinout the addresses as

4-0;(leave other jumper off?) /:/ 4-0;1-0


i guess i need a scsi ID priority course huh?

 

[technome]

Not geting into the jumpers...
Placing more than 3 to 4 u320 drives on a cable is asking for problems due to attenuation. You need an SCA backplane

Do you have the tape unit on the Perc, if so your asking for disaster, needs to be on it own scsi channel with NO drives.

Placing more than 4 u320 drives on a scsi channel will cause bus saturation.

........................................
Chernobyl disaster..a must see pictorial

http://www.kiddofspeed.com/default.htm

 

[adamroof]

Well, per your other responses, i did what had to be done for now.

i finally dug out the manual for these cheetah seagate drives and got the right pin placement.

http://www.seagate.com/support/disc/manuals/scsi/100148123b.pdf

the ids are 4 and 5 and it recognizes just fine, and was able to add the second virtual disk with a RAID 1 on the 2 new drives in minutes.

the tape is on its own controller as i stated above.

IRT your statements's
so, how long would you say until bus saturation is prevelent?
why then does u320 state it supports 16 devices?
Why would "they" sell u320 7 device cables?
Why does SCSI support Daisy chaining up to 15 devices
Why does the above manual from seagate not mention bus saturation even once?

 

[scsiraid]

Bus saturation depends totally on workload, not number of drives. Transaction workloads come nowhere near saturating SCSI with 14 drives. 14 drives at 200 IOPS per drive with 16K per IO is under 50MB/sec. Sequential workloads are a different story. 4 drives could saturate the bus with transfer rates near 100MB/Sec. One problem you can run into with many drives is signal quality. The more stubs and loads on the bus, the worse the signal looks.