How to find the local disks and SAN disks in linux

[senthil_kumar_1]

Hi

I have following questions pls answer my questions.

1) when list /sys/block it shows that following disks are available like c0d0, sda, sdb, sddlmab, sddlmac, sddlmfdrv0.

Ex:
# cd /sys/block
# ll

drwxr-xr-x 5 root root 0 Feb 27 21:25 cciss!c0d0
drwxr-xr-x 5 root root 0 Feb 27 21:25 sda
drwxr-xr-x 3 root root 0 Feb 27 21:25 sdb
drwxr-xr-x 2 root root 0 Feb 27 21:26 sddlmab
drwxr-xr-x 4 root root 0 Feb 27 21:26 sddlmac
drwxr-xr-x 2 root root 0 Feb 27 21:26 sddlmfdrv0


But when I execute "lsscsi" i am only seeing two disks sda and sdb. whe we can not see other disks.

Ex:

[0:0:1:0] disk HITACHI OPEN-V*3 6004 /dev/sda
[0:0:1:1] disk HITACHI OPEN-V*5 6004 /dev/sdb



2) Pls explain the first four digits.

Ex:

0:0:1:0 --->/ded/sda

here pls explain what is 0:0:1:0

[Sivakumar MJ._1]

Senthil,

Check the man pages, Its explains

http://linux.die.net/man/8/lsscsi

[Uwe Zessin]

"lsscsi" shows all devices (disks, tapes, controllers, ...) handled by the SCSI layer, but some devices (e.g. cciss!c0d0) come from a different handler 'parallel' to the SCSI layer.

[view with a fixed font]
+---------------------+
| ___block-devices___ |
+------+--------+-----+
| SCSI | CCISS. | ... |
+------+--------+-----+

cciss is a SmartArray RAID controller which hides the physical parallel SCSI, SAS and SATA disk drives from the SCSI layer.

sddlmab - this seems to be a 'pseudo' device created by Hitachy multipath software.


0:0:1:0

0 - host adapter number
0 - channel index on this adapter
1 - SCSI target ID on this channel
... (points to a target port in the Fibre Channel fabric)
0 - LUN address on this SCSI target

[senthil_kumar_1]

Hi Uwe Zessin,

pls check my understanding is correct.

cciss --> is smart raid array controller.
that is some scsci hdds are controlled by this. and created raid.

sda, sdb ---> here it is SAN disks.

sddlmab --> this seems to be a 'pseudo' device created by Hitachy multipath software.

so this "sddlmab" is also a SAN disk.

we are using qlogic HBA card.


I have follwoing questions:

1) how to find how many qlogic card has been installed.

2) how it is possible that some SAN disks are sda, sdb and some disks are sddlmab, sddlmac.

3) how to find the real device of sddlmab.

pls explain me.

[Uwe Zessin]

cciss: correct

sda+sdb: in this situation, true, but on some other system 'sda', for example can be a simple parallel SCSI disk attached to a simple host bus adapter. I have also seen 'sda,sdb,...' being used by some DELL RAID controllers.

sddlmab: kind of, yes. It is usually used for path failover, but it seems there are is no redundant path on the second FC port.


1): as far as I know, depending on the Linux distribution there are different commands, e.g.:
# lspci

You can also check /proc/scsi. In most cases you will see a directory like 'qla2300' which contains information about each port (a dual-port adapter will have 2 entries), e.g.
[root@esxc root]# cat /proc/scsi/qla2300/2
QLogic PCI to Fibre Channel Host Adapter for QLA2340 :
........Firmware version: 3.03.19, Driver version 7.08-vm33.3

(This is from the 'service console' of a VMware ESX server which is a special paravirtualized Linux-VM).


2): it all depends on the device driver(s)


3): Such solutions usually have a command interface. I am not a specialist in Hitachi storage, but a small web search points to "Dynamic Link Manager" and the "dlnkmgr" commmand, e.g.:
# dlnkmgr view -path

[root4sp]

You can use the lsblk command to display blocks in structurewise..

Note: If command not found, you can find it. =>  yum provides */lsblk