SureStore E SC10

[Werner Vergauwen]

Hi,

I would like to know how this works on the inside : are the 2 BCCs on the same bus; how do they divide the workload; how to connect multiple hosts for HA.

I am very disappointed about the documentation : rambling about for pages on how to install some rails, but merely a mentioning diagram on how to REALLY connect the stuff.

BTW, the entire config (2 servers + 2 sc10 + rack) was dropped into our offices without anybody even telling us what it all was for...!

[Bob Inglis · Accepted solution]

Werner,

You are correct, the SC10 User/Service manual does a poor job describing the operation and configuration of the storage enclosure.

Let me try to describe it ?in a nut shell?.

The SC10 storage enclosure can contain up to 10 Disk Mechanisms and can be configured for Full Bus Mode; all 10 drives and both Bus Control Cards (BCC?s) on a single SCSI Bus or it can be configured for Split Bus Mode with two independent SCSI Busses of 5 drives each and one Bus Control Card on each.

Each Bus Control Card has 2 Low Voltage Differential SCSI connectors for connecting to multiple hosts systems or for daisy-chaining additional storage enclosures.

From here on I can only guess at how you may want to configure your system.
It would depend on how many Host Bus Adapters there are in each system.

Disk mirroring is usually done between drives on different SCSI busses.

High Availability is accomplished by connecting two different Host systems to each SCSI Bus.

With two SC10 disk enclosures I would set each of them up in full bus mode and connect one BCC on each SC10 to a Host Bus Adapter on each system. Note: Host Bus Adapters are shipped set to SCSI address 7, the SCSI address of the Host Bus adapter in one system will have to be changed to 6 to avoid an address conflict.

Use LVM mirroring to mirror each drive in the first SC10 to the respective drive in the second SC10.

LVM alternate Links would require two more Host Bus Adapters in each system. This gets tricky as you don?t want both Host Bus Adapters on a system connected to the same Bus Control Card in a SC10. Thus you must ?chris-cross? the cables. Note: Now you have 4 Host Bus Adapters on each SCSI bus so you need to set their SCSI addresses to 5 and 4 respectivly.

Further Note: In Full bus mode the drives are set to SCSI addresses 0, 1, 2, 3, 8, 9, 10, 11, 12 & 13 by their position in the enclosure and the BCC?s are at SCSI address 14 & 15. With 4 Host Bus Adapters set to 7, 6, 5 & 4 all possible bus addresses are in use, thus ?daisy-chaining? additional enclosures would not be possible.

Bob

[Werner Vergauwen]

Bob,

I am really impressed with your answer: it was what I needed to get the job done on the SC10. (SCSI INIT does not work yet).

The key sentence here is actually : "all 10 drives and both BCC's are on a single SCSI bus, or ..." If this sentence had been in the manual, everything would have made sense.

good job!!