Solaris 9 - Fibre2SCSI Bridge/Storage Router -throughput/scsi target ques.
Hello.
I currently have a Solaris 9 host connected via fibre to a Crossroads 10000 Fibre to SCSI bridge. The Crossroads storage router has a 4 channel SCSI module, to which 4 SDLT tape drives are connected (each on their own bus).
The problem is this:
When the Solaris host is connected to the Crossroads via a single fibre connection, all four drives appear to be on the same bus from the Solaris host's point of view. The result of this is that the COMBINED throughput to all of the devices is 40 MB/s. When the Solaris host is connected to a second port of the Crossroads storage router, it sees the second port as a separate target, effectively doubling the throughput.
For example, in the following configuration, the COMBINED throughput to these drives is limited by Solaris to 40MB/s, even though each is capable of 40MB/s on its own. Note that the target (st@<target>,<lun>) is the same for each tape. This is the case when the Solaris host is connected to a single port on the storage router.
/dev/rmt/6cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,4:cbn
/dev/rmt/7cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,3:cbn
/dev/rmt/8cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,2:cbn
/dev/rmt/9cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,1:cbn
In this next example, the Solaris host is connected to two ports on the Crossroads, which results in the host seeing two separate targets. In this case the combined throughput is 80MB/s, with 40MB/s available for the two drives oneach target. Note that the target for 10cbn and 11cbn is different than 8cbn and 9bn.
/dev/rmt/10cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fc,4:cbn
/dev/rmt/11cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fc,3:cbn
/dev/rmt/8cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,2:cbn
/dev/rmt/9cbn ->../../devices/pci@8,700000/SUNW,qlc@3,1/fp@0,0/st@w100000e0020236fa,1:cbn
One solution for the problem is to use a separate fibre port on the storage router for each SCSI bus. However, the ideal solution would be one in which I could use a single fibre port and achieve the full 160MB/s (40MB/s per SCSI bus).
Is anyone aware of a way to tell Solaris that it should treat each device as if it has its own bus?
Thanks!
-Will
