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$FreeBSD$
.Dd November 15, 2002 .Dt SCSI_TARGET 8 .Os .Sh NAME .Nm scsi_target .Nd usermode SCSI disk emulator .Sh SYNOPSIS .Nm .Op Fl AdST .Op Fl b Ar size .Op Fl c Ar size .Op Fl s Ar size .Op Fl W Ar num .Ar bus : Ns Ar target : Ns Ar lun .Ar filename .Sh DESCRIPTION The .Nm utility emulates a SCSI target device using the .Xr targ 4 device driver. It supports the basic commands of a direct access device, like .Xr da 4 . In typical operation, it opens a control device and enables target mode for the specified LUN. It then communicates with the SIM using CCBs exchanged via .Xr read 2 and .Xr write 2 . READ and WRITE CDBs are satisfied with the specified backing store file.
p For performance, all backing store accesses use .Xr aio 4 . Thus, .Nm requires a kernel compiled with .Cd "options VFS_AIO" .
p Options: l -tag -width indent t Fl A Enable 16 addresses if supported by the SIM. Default is 8. t Fl S Enable synchronous transfers if supported by the SIM. Default is disabled. t Fl T Enable tagged queuing if supported by the SIM. Default is no tagged queuing. t Fl W Cm 8 | 16 | 32 Enable 16 or 32 bit wide transfers if supported by the SIM. Default is 8. t Fl b Ar bufsize Set buffer size for transfers. Transfers larger than this will be split into multiple transfers. t Fl c Ar sectorsize Set sector size for emulated volume. Default is 512. t Fl d Enable debugging output in .Nm and its associated control device. t Fl s Ar volsize Use a different size for the emulated volume. Must be less than or equal to the size of .Ar filename . If the number ends with a .Dq Li k , .Dq Li m , .Dq Li g , .Dq Li t , .Dq Li p , or .Dq Li e , the number is multiplied by 2^10 (1K), 2^20 (1M), 2^30 (1G), 2^40 (1T), 2^50 (1P) and 2^60 (1E) respectively. .El
p Required arguments: l -tag -width indent t Ar bus : Ns Ar target : Ns Ar lun Attach to specified bus ID, target ID, and LUN. t Ar filename File to use as a backing store. .El
p All options default to the minimal functionality of SCSI-1. To be safe, .Nm checks the SIM for the requested capability before enabling target mode. .Sh FILES l -tag -width ".Pa /usr/share/examples/scsi_target" -compact t Pa /dev/targ* Control devices. t Pa /usr/share/examples/scsi_target Source directory. .El .Sh EXAMPLES Create a 5 megabyte backing store file.
p .Dl "dd if=/dev/zero of=vol size=1m count=5"
p Enable target mode on bus 0, target ID 1, LUN 0, using
a vol as the backing store for READ6/10 and WRITE6/10 commands. Only the first 1000 bytes of
a vol will be used. Debugging information will be output. 16-bit wide transfers will be used if the SIM supports them.
p .Dl "scsi_target -d -s 1000 -W 16 0:1:0 vol" .Sh SEE ALSO .Xr scsi 4 , .Xr targ 4 .Sh AUTHORS .An -nosplit The .Nm example first appeared in .Fx 3.0 and was written by .An Justin T. Gibbs . It was rewritten for .Fx 5.0 by .An Nate Lawson Aq Mt nate@root.org .