Douglas Gilbert wrote: > john clyne wrote: >> What do the different hostX in /sys/class/scsi_host corespond to? There are >> seven hostX directories, 5 with sg_tablesize set to 128 and two set to 255. > > A Linux "host" is a SCSI initiator port (e.g. FC) or a > SCSI initiator device (e.g. SAS). Another way of looking > at a "host" is as a bridge between a computer bus (e.g. PCI) > and a storage transport. There is usually one (low level) > driver (LLD) controlling all hosts associated with a > specific class of hardware. > > If you fetch the lsscsi utility and load it then you can > try 'lsscsi --hosts' to list the active hosts on a > system (numbered on the left) and see the names of the > various LLDs associated with them. Here is an example: > > # lsscsi --hosts > [0] sata_nv > [1] sata_nv > [2] sata_nv > [3] sata_nv > [4] mptsas > [5] aic94xx > [6] sbp2 > > The first four are SATA ports (connectors) on the motherboard, > all controlled by the same driver. Then there is a LSI SAS > HBA (whose driver is mptsas), an Adaptec SAS HBA (48300) and > finally an Adaptec IEEE 1394 controller. A side note: I don't think a Scsi_Host has a well-defined meaning beyond "the kernel-internal resource which LLDs use to connect to the Linux SCSI mid layer". It may have further meaning for many LLDs, but not for all. Specifically, the host6 in your example is in the current implementation indeed nothing more than an internal resource. lsscsi is nevertheless able to determine the actual initiator port by means of knowledge of the implementation. -- Stefan Richter -=====-=-=== ---= -=-== http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
