System information
Note
The older form of this command, echo "scsi ad d -si ng l e-d evi ce 0 0 0 0 " >
/pro c/scsi /scsi , is deprecated.
a. In some Fibre Channel hardware, a newly created LUN on the RAID array may not be
visible to the operating system until a Loop Initialization Protocol (LIP) operation is
performed. Refer to Section 25.9, “ Scanning Storage Interconnects” for instructions
on how to do this.
Important
It will be necessary to stop I/O while this operation is executed if an LIP is
required.
b. If a new LUN has been added on the RAID array but is still not being configured by
the operating system, confirm the list of LUNs being exported by the array using the
sg _l uns command, part of the sg3_utils package. This will issue the SC SI R EP OR T
LUNS command to the RAID array and return a list of LUNs that are present.
For Fibre Channel storage servers that implement a single WWNN for all ports, you can
determine the correct h,c,and t values (i.e. HBA number, HBA channel, and SCSI target ID)
by searching for the WWNN in sysfs.
Examp le 25.4 . Det ermin correct h, c, an d t values
For example, if the WWNN of the storage server is 0 x50 0 60 16 0 9 0 20 3181, use:
$ grep 5006016090203181 /sys/class/fc_transport/*/node_name
This should display output similar to the following:
/sys/class/fc_transport/target5:0:2/node_name:0x5006016090203181
/sys/class/fc_transport/target5:0:3/node_name:0x5006016090203181
/sys/class/fc_transport/target6:0:2/node_name:0x5006016090203181
/sys/class/fc_transport/target6:0:3/node_name:0x5006016090203181
This indicates there are four Fibre Channel routes to this target (two single-channel HBAs,
each leading to two storage ports). Assuming a LUN value is 56 , then the following
command will configure the first path:
$ echo "0 2 56" > /sys/class/scsi_host/host5/scan
This must be done for each path to the new device.
For Fibre Channel storage servers that do not implement a single WWNN for all ports, you
can determine the correct HBA number, HBA channel, and SCSI target ID by searching for
each of the WWPNs in sysfs.
Another way to determine the HBA number, HBA channel, and SCSI target ID is to refer to
Chapt er 2 5. O nline St orag e Manag ement
175