Centos 7 server isn't able to see fiber channel LUN SCSI devices

Question

I have a Fiber channel connected via SCSI SAN that I am not able to see. I would like to be able to access these drives as if they were mounted.

Perhaps the entire thing is I have no to little experience with SCSI devices , but I expected to see something in /dev/ and I don't.

Here are some commands of what I am able to see and it looks like my server sees the card but doesn't make a device of it? I was leaning on this being a potential driver issue , but I am not certain.

Hopefully this is not something needing a search in forum redirect, but let me know if this is something that is too far out of scope.

Even if it ends up being a link to something to read to understand this better here I will happily accept it if it helps me solve this.

 lspci -nn | grep "Fibre Channel"
0d:00.0 Fibre Channel [0c04]: QLogic Corp. ISP2432-based 4Gb Fibre Channel to PCI Express HBA [1077:2432] (rev 03)
0d:00.1 Fibre Channel [0c04]: QLogic Corp. ISP2432-based 4Gb Fibre Channel to PCI Express HBA [1077:2432] (rev 03)

>

[root@ ~]# dmesg | grep HUASY
[    3.377927] scsi 0:0:0:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[    3.419624] scsi 0:0:1:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[    3.717599] scsi 1:0:0:0: Direct-Access     HUASY    Dorado2100       2    PQ: 1 ANSI: 4
[    3.755084] scsi 1:0:1:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[    3.796961] scsi 1:0:2:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[    4.371104] scsi 0:0:2:0: Direct-Access     HUASY    Dorado2100       2    PQ: 1 ANSI: 4
[ 1173.634215] scsi 0:0:0:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[ 1173.675895] scsi 0:0:1:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[ 1173.719362] scsi 0:0:2:0: Direct-Access     HUASY    Dorado2100       2    PQ: 1 ANSI: 4
[ 1177.544427] scsi 1:0:0:0: Direct-Access     HUASY    Dorado2100       2    PQ: 1 ANSI: 4
[ 1177.581499] scsi 1:0:1:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4
[ 1177.623165] scsi 1:0:2:0: Direct-Access     HUASY    S5500T           2    PQ: 1 ANSI: 4

Shouldn't I see a /dev/device name for all these devices?

 lsscsi
[0:0:0:0]    disk    HUASY    S5500T           2     -        
[0:0:1:0]    disk    HUASY    S5500T           2     -        
[0:0:2:0]    disk    HUASY    Dorado2100       2     -        
[1:0:0:0]    disk    HUASY    Dorado2100       2     -        
[1:0:1:0]    disk    HUASY    S5500T           2     -        
[1:0:2:0]    disk    HUASY    S5500T           2     -        
[2:0:0:0]    cd/dvd           Virtual CDROM    1.00  /dev/sr0 
[3:0:0:0]    disk             Virtual Floppy   1.00  /dev/sda 
[4:0:0:0]    disk    SEAGATE  ST973402SS       S229  -        
[4:0:1:0]    disk    SEAGATE  ST973402SS       S229  -        
[4:1:0:0]    disk    Dell     VIRTUAL DISK     1028  /dev/sdb

>

 rescan-scsi-bus.sh 
Scanning SCSI subsystem for new devices
Scanning host 0 for  all SCSI target IDs, all LUNs
sg2 changed: LU not available (PQual 1)    
OLD: Host: scsi0 Channel: 00 Id: 00 Lun: 00
      Vendor: HUASY    Model: S5500T           Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
sg3 changed: LU not available (PQual 1)    
OLD: Host: scsi0 Channel: 00 Id: 01 Lun: 00
      Vendor: HUASY    Model: S5500T           Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
sg4 changed: LU not available (PQual 1)    
OLD: Host: scsi0 Channel: 00 Id: 02 Lun: 00
      Vendor: HUASY    Model: Dorado2100       Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
Scanning host 1 for  all SCSI target IDs, all LUNs
sg5 changed: LU not available (PQual 1)    
OLD: Host: scsi1 Channel: 00 Id: 00 Lun: 00
      Vendor: HUASY    Model: Dorado2100       Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
sg6 changed: LU not available (PQual 1)    
OLD: Host: scsi1 Channel: 00 Id: 01 Lun: 00
      Vendor: HUASY    Model: S5500T           Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
sg7 changed: LU not available (PQual 1)    
OLD: Host: scsi1 Channel: 00 Id: 02 Lun: 00
      Vendor: HUASY    Model: S5500T           Rev: 2   
      Type:   Direct-Access                    ANSI SCSI revision: 04
Scanning host 2 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
 Scanning for device 2 0 0 0 ...           
OLD: Host: scsi2 Channel: 00 Id: 00 Lun: 00
      Vendor:          Model: Virtual CDROM    Rev: 1.00
      Type:   CD-ROM                           ANSI SCSI revision: -1
Scanning host 3 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
 Scanning for device 3 0 0 0 ...           
OLD: Host: scsi3 Channel: 00 Id: 00 Lun: 00
      Vendor:          Model: Virtual Floppy   Rev: 1.00
      Type:   Direct-Access                    ANSI SCSI revision: -1
Scanning host 4 for  SCSI target IDs  0 1 2 3 4 5 6 7, all LUNs
 Scanning for device 4 0 0 0 ... 
NEW: Host: scsi4 Channel: 00 Id: 00 Lun: 00
      Vendor: SEAGATE  Model: ST973402SS       Rev: S229
      Type:   Direct-Access                    ANSI SCSI revision: 05
 Scanning for device 4 0 1 0 ... 
NEW: Host: scsi4 Channel: 00 Id: 01 Lun: 00
      Vendor: SEAGATE  Model: ST973402SS       Rev: S229
      Type:   Direct-Access                    ANSI SCSI revision: 05
 Scanning for device 4 1 0 0 ...           
OLD: Host: scsi4 Channel: 01 Id: 00 Lun: 00
      Vendor: Dell     Model: VIRTUAL DISK     Rev: 1028
      Type:   Direct-Access                    ANSI SCSI revision: 05
2 new or changed device(s) found.          
    [4:0:0:0]
    [4:0:1:0]
0 remapped or resized device(s) found.      
0 device(s) removed.

Look at the rest of the `dmesg` messages that you filtered out. — Michael Hampton, Sep 04 '18 at 12:22

score 1 · Answer 1 · answered Sep 04 '18 at 12:17

First, Find out how many host bus adapter configured in the Linux box. you can use “systool -fc_host -v to verify available FC in the system.

# ls /sys/class/fc_host
host0  host1

In this example,you need to scan host0 & host1 HBA.

If the system virtual memory is too low ,then do not proceed further.If you have enough free virtual memory,then you can proceed with below command to scan new LUNS.

# echo "1" > /sys/class/fc_host/host0/issue_lip
# echo "1" > /sys/class/fc_host/host1/issue_lip

Note: You need to monitor the “issue_lip” in /var/log/messages to determine when the scan will complete.This operation is an asynchronous operation.

Next, Verify if the new LUN is visible or not by counting the available disks.

# fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l

If any new LUNS added ,then you can see more count is more then before scanning the LUNS.

Also, you may see the added disks by running lsblkor

ls -l /dev/disk/by-path/*
...
lrwxrwxrwx 1 root root 10 Aug 15 16:49 /dev/disk/by-path/pci-0000:15:00.1-fc-0x22430080e524ebac-lun-4 -> ../../sdcx
lrwxrwxrwx 1 root root 10 Aug 15 16:49 /dev/disk/by-path/pci-0000:15:00.1-fc-0x22430080e524ebac-lun-5 -> ../../sdcy

From which you'll be able to identify the FC block device.

I think the problem is that I have a Qlogic QME2472 I might need to look and see what is the deal with it. — LUser, Sep 06 '18 at 11:12
also for the lsscsi command. Shouldn't I see those devices after them ? — LUser, Sep 07 '18 at 14:54

Centos 7 server isn't able to see fiber channel LUN SCSI devices

1 Answers1