On Dec 21, 2011, at 3:14 AM, James C. McPherson wrote: > On 21/12/11 05:58 PM, Matthew R. Wilson wrote: >> Hello, >> >> I am curious to know if there is an easy way to guess or identify the >> device names of disks. Previously the /dev/dsk/c0t0d0s0 system made sense >> to me... I had a SATA controller card with 8 ports, and they showed up >> with the numbers 1-8 in the "t" position of the device name. >> >> But I just built a new system with two LSI SAS HBAs in it, and my device >> names are along the lines of: >> /dev/dsk/c0t5000CCA228C0E488d0 >> >> I could not find any correlation between that identifier and the a) >> controller the disk was plugged in to, or b) the port number on the >> controller. The only way I could make a mapping of device name to >> controller port was to add one drive at a time, reboot the system, and run >> "format" to see which new disk name shows up. >> >> I'm guessing there's a better way, but I can't find any obvious answer as >> to how to determine which port on my LSI controller card will correspond >> with which seemingly random device name. Can anyone offer any suggestions >> on a way to predict the device naming, or at least get the system to list >> the disks after I insert one without rebooting? > > Hi Matthew, > By default the names for disks attached via mpt_sas(7d), or > mpt(7d) if your disks are new enough, is to use their WWN > as reported in the SCSI INQUIRY Page83 response. > > The old paradigm you refer to is based on the physical id > of the device on a parallel SCSI bus. That doesn't scale > with SAS, and is something we're trying to move away from.
More to the point, on SAS and other similar busses, there simply *isn't* such a thing as a simple target number. The old numbering scheme from parallel SCSI was suitable when you could have only 7 or 15 or so devices on a single bus. With modern busses you can have many thousands of devices on the same fabric. So we address them by WWN. - Garrett > > If you'd like some info about how we use devids and guids, > please refer to my presentation > > http://www.jmcp.homeunix.com/~jmcp/WhatIsAGuid.pdf > > > For your particular configuration, if you note the serial > number and WWN of the device before you insert them, you > can match that up with info from iostat -En and/or prtconf -v. > > > hth, > James C. McPherson > -- > Oracle > http://www.jmcp.homeunix.com/blog > _______________________________________________ > zfs-discuss mailing list > firstname.lastname@example.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list email@example.com http://mail.opensolaris.org/mailman/listinfo/zfs-discuss