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Problem add SCSI device above sdz / qlogic hba

 
weisstik
Advisor

Problem add SCSI device above sdz / qlogic hba

First of all I want to say hello to the forum :)

I have one question. We are running RHEL 4 AS Update 5 on a HP DL585 with two FC1142SR HBAs and we aren't able to add devices above SDZ. The only thing that helps, is to reboot the server. In two weeks the server will be in a productive state and so we won't be allowed to reboot the server everytime we are adding a LUN.

First i had problem that the LUNs weren't recognized by the Qlogic driver. I tried the following command

echo scsi-qlascan >/proc/scsi/qla2xxx/1

and after that the LUNs were available. I have also tried the HP_RESCAN script, but it also haven't helped to create the device drivers.

Furthermore i tried this command

echo "scsi add-single-device A B T L">/proc/scsi/scsi

The device driver was not created and now i am not sure if the problem is that we have already reached the /dev/sdz device driver.

Does anyone know where this behaviour is handeld or where i can find these regexp?

Thank you in advance

greets
4 REPLIES
Matti_Kurkela
Honored Contributor

Re: Problem add SCSI device above sdz / qlogic hba

The device _driver_ may be OK, but you're apparently missing the device _nodes_, i.e. the file-like things in /dev.

In any relatively modern Linux, the device nodes are managed by "udev". Udev has a lot of configuration rules: they can be found in /etc/udev/rules.d. There are also several commands that might help in finding the problem: "udevmonitor" allows you to find out exactly what udev is doing, and "udevtrigger" can be used to reload the rules after you've changed them.

If you prefer to create the device nodes manually using mknod, create them in /dev/.static/dev: any device nodes created there will be persistently stored on the system disk and will be automatically replicated to the real /dev when the system starts up.

(When udev is used, the real /dev is generated dynamically on a tmpfs filesystem, i.e. a RAM disk.)

MK
MK
weisstik
Advisor

Re: Problem add SCSI device above sdz / qlogic hba

Thank yo for your answer. Yes, i mean the device files, they aren't existing.

I have already sawn through the udev rules but i haven't found anything appropriate for the sd driver.

I wasn't able to locate the udevmonitor oder udevtrigger on Red Hat EL 4 Update 5. I will have a look on rpmseek for that tool.

Makedev is also responsible for this process but i think, that it only takes place in the boot process?!

Do I have to create the /dev/.static/ directory or should it already exists?

Thank you in advance

weisstik
Advisor

Re: Problem add SCSI device above sdz / qlogic hba

Hello,

i was able to reproduce the process and solve the problem with the following commands.


echo scsi-qlascan>/proc/scsi/qla2xxx/0
echo scsi-qlascan>/proc/scsi/qla2xxx/1

echo "- - -" > /sys/class/scsi_host/host1/scan
echo "- - -" > /sys/class/scsi_host/host0/scan

The LUNs were found and the device files created and all is working well.
weisstik
Advisor

Re: Problem add SCSI device above sdz / qlogic hba

Hello,

i was able to reproduce the process and solve the problem with the following commands.


echo scsi-qlascan>/proc/scsi/qla2xxx/0
echo scsi-qlascan>/proc/scsi/qla2xxx/1

echo "- - -" > /sys/class/scsi_host/host1/scan
echo "- - -" > /sys/class/scsi_host/host0/scan

The LUNs were found and the device files created and all is working well.