topic Re: Need Help - RHEL 4 in Operating System - Linux

Need Help - RHEL 4

S.S. — Mon, 22 Mar 2010 06:44:44 GMT

Hi,

Our server is Linux RHEL 4.

1.] How to check that HBA card on the server working?

2.] How to check that the fibre channel cables are any faulty?

3.]I want to do a test that to create a 1gb vidks in EVA and want to mount it on the Linux Server. How can i do this?

4.] How to Check the fibre switches status are okay.

Thank you.

Re: Need Help - RHEL 4

Thomas Vogt (CH) — Mon, 22 Mar 2010 09:43:19 GMT

Hi,

1. # lsscsi

2. # multipath -ll

-----------------------------------------
3. Howto:

# multipath -ll

mpath0 (3600508b400070aac0000900000080000) dm-1 HP,HSV200
[size=10G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=4][active]
\_ 0:0:0:1 sda 8:0 [active][ready]
\_ 0:0:1:1 sdb 8:16 [active][ready]
\_ 1:0:0:1 sdc 8:32 [active][ready]
\_ 1:0:1:1 sdd 8:48 [active][ready]

# fdisk /dev/sda

# kpartx -a /dev/mapper/mpath0

# ls /dev/mapper/*
mpath0 mpath0p1

# mkfs.ext3 /dev/mapper/mpath0p1

# mount /dev/mapper/mpath0p1 /mnt/san
-----------------------------------------

More Infos:
http://thomasvogt.wordpress.com/2007/11/29/linux-san-multipathing/

Hope it helps.

Cheers
- Thomas

Re: Need Help - RHEL 4

Hemmetter — Mon, 22 Mar 2010 10:19:28 GMT

Hi

you can also check e.g. ( Emulex )

# cat /sys/class/scsi_host/host3/state
Link Up - Ready
Fabric

# cat /sys/class/scsi_host/host3/lpfc_link_speed
0 # i.e. autodetect

rgds
HGH

Re: Need Help - RHEL 4

Matti_Kurkela — Mon, 22 Mar 2010 13:04:54 GMT

Note to other posters: this is about RHEL 4, so e.g. the lsscsi command is not available.

1.) Is HBA working?

There are several ways to test this.

a) does it have a connection to SAN?

For Emulex cards:
cat /sys/class/scsi_host/host*/state

For Qlogic qla2xxx cards:
grep state /proc/scsi/qla2xxx/*

b) does it see any FibreChannel targets?

For Emulex cards:
cat /sys/class/scsi_host/host*/disc_map

For Qlogic qla2xxx cards:
grep target /proc/scsi/qla2xxx/*

c) can it access the disks?

touch /fc_mountpoint/testfile
rm /fc_mountpoint/testfile

2.) How to check FC cables?

Use a FC cable tester.
- simple test: does the light pass through the cable at all?
- advanced test: does the cable pass _enough_ light to the destination?

Don't try to verify the cable by connecting one end to a transmitter and looking with your bare eyes at the other end.

Remember, the laser light used in FC connections is mostly invisible. The short-wave (short-haul) laser light is barely visible as a deep red color, but as a significant part of the power is in infra-red light, it's more powerful than it looks like.

The light in the long-wave (long-haul) connections is wholly infrared and more powerful: you don't see it at all, but it can still cause permanent damage to your eyes.

The standard half-joke: "Don't look into the fibre with the remaining eye!"

3.) How to present a LUN and mount it as a test?

You configure EVA and the FC switches with the tools of your choice. This part has nothing to do with Linux.

Then follow the procedures in RedHat Online Storage Reconfiguration Guide (link below) to detect it, then partition it, create a filesystem and mount it according to your site's standard policy.

https://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/html/Online_Storage_Reconfiguration_Guide/index.html

Did you wish to automate this? It would require some rather complex and site-specific scripting. A malfunctioning script might damage production disk configurations, so your script should be very very careful about error situations.

4.) How to check FC switch status?

Please read the manual of the switch. The FC switches usually have LAN connections for management, and offer various industry-standard monitoring protocols, like SNMP. Setting up an automated monitoring for FC switch status is usually very easy.

MK

Re: Need Help - RHEL 4

S.S. — Thu, 01 Apr 2010 07:30:43 GMT

Thank you.