my VMKernel logs have been fairly clean since I changed my iSCSI Daemon tuning options to what Todd recommended.

I am still getting these messages though in my VMKernel logs on ESX4.0:

Jun 5 11:08:57 vmhost-1 vmkernel: 6:01:50:02.470 cpu6:5337)ScsiScan: 105: Path 'vmhba33:C0:T2:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.469 cpu4:5340)ScsiScan: 839: Path 'vmhba33:C0:T1:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.469 cpu4:5340)ScsiScan: 842: Path 'vmhba33:C0:T1:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.469 cpu4:5340)ScsiScan: 105: Path 'vmhba33:C0:T1:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.470 cpu4:5340)ScsiScan: 839: Path 'vmhba33:C0:T2:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.470 cpu4:5340)ScsiScan: 842: Path 'vmhba33:C0:T2:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:13:57 vmhost-1 vmkernel: 6:01:55:02.470 cpu4:5340)ScsiScan: 105: Path 'vmhba33:C0:T2:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.469 cpu6:4171)ScsiScan: 839: Path 'vmhba33:C0:T1:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.469 cpu6:4171)ScsiScan: 842: Path 'vmhba33:C0:T1:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.469 cpu6:4171)ScsiScan: 105: Path 'vmhba33:C0:T1:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.470 cpu6:4171)ScsiScan: 839: Path 'vmhba33:C0:T2:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.470 cpu6:4171)ScsiScan: 842: Path 'vmhba33:C0:T2:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:18:57 vmhost-1 vmkernel: 6:02:00:02.470 cpu6:4171)ScsiScan: 105: Path 'vmhba33:C0:T2:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.701 cpu7:5341)ScsiScan: 839: Path 'vmhba33:C0:T1:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.701 cpu7:5341)ScsiScan: 842: Path 'vmhba33:C0:T1:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.701 cpu7:5341)ScsiScan: 105: Path 'vmhba33:C0:T1:L0': Peripheral qualifier 0x3 not supported
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.702 cpu7:5341)ScsiScan: 839: Path 'vmhba33:C0:T2:L0': Vendor: 'iSCSI ' Model: 'DISK ' Rev: '0 '
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.702 cpu7:5341)ScsiScan: 842: Path 'vmhba33:C0:T2:L0': Type: 0x1f, ANSI rev: 4, TPGS: 0 (none)
Jun 5 11:23:57 vmhost-1 vmkernel: 6:02:05:02.702 cpu7:5341)ScsiScan: 105: Path 'vmhba33:C0:T2:L0': Peripheral qualifier 0x3 not supported