Setting up Redhat AS3 on a terminal server

[f0rmat]

I've read through a few posts and think I might have an idea, but just wanted to post to see if there's anything I'm overlooking and to get some clarification.

I've purchased a 48port terminal console server, with the intentions of hooking up all my *nix boxes for console connections. Solaris/sparc works fantastic, however I can't get my linux boxes working yet. I'm running on a Dell Poweredge 1950 with serial console redirection turned on in the BIOS, redirecting to com 1(tried both com 1 and 2) and the baud set to 57600 as a failsafe, I had tried hardcoding this to 9600 as well.

For whatever reason when I try to direct connect to the port, I get no responses. Is there something in linux(the OS itself) that I need to enable? Ive read posts about setting a terminal setting in the boot loader, which I haven't done yet because I don't know exactly what it is I need to enter into the conf file, but even then I think I should be able to access the machine as it boots up(as with solaris) so if I'm connected and I reboot I'll see the hardware initializations etc..

Any help is most appreciated!

 

[Annihilannic]

We use Cyclades TS-2000 and 3000s for this job on Dell servers that are not equipped with a DRAC (Dell Remote Access Controller).

I'm not familiar with the serial console redirection you describe in the BIOS, and I'd be curious to hear about it as we currently have no lights-out management capability for servers without DRACs. Is it a new feature in the x9xx series of servers?

To enable the serial console from the point the Linux kernel boots though you need to append "console=ttyS0,9600" to the kernel command line, either in your grub or lilo config file.

To accept logins on that serial console you need to add the following to /etc/inittab to start a getty against it:

[tt]# Run gettys in standard runlevels
1:2345:respawn:/sbin/mingetty tty1
2:2345:respawn:/sbin/mingetty tty2
3:2345:respawn:/sbin/mingetty tty3
4:2345:respawn:/sbin/mingetty tty4
5:2345:respawn:/sbin/mingetty tty5
6:2345:respawn:/sbin/mingetty tty6
S0:12345:respawn:/sbin/mgetty -r -s 9600 ttyS0[/tt]

Annihilannic.

 

[f0rmat]

it may be a new feature, I'm not sure. I also have some PE850's and 1850's but I haven't checked the BIOS's on those yet. I also have about 10/15 linux and solaris boxes which are Precision 530's/650's/670's and I don't know if I can do a console redirect through the serial on those since they are just workstations, but I will see.

Once I'm back in the office on monday I'll post the various options of the BIOS setting on the x9xx series I have.

Quick question about the console line in the grub file, if the filesystem is in a hung state, and I can not telnet, ssh, rlogin whatever.. to it, will I still be able to get to the machine using the terminal server, with this config setup? I would assume yes, unless the kernel itself is crashed. This will also limit me to a console connection right after the point of the kernal loading after grub, correct?

 

[Annihilannic]

Quick question about the console line in the grub file, if the filesystem is in a hung state, and I can not telnet, ssh, rlogin whatever.. to it, will I still be able to get to the machine using the terminal server, with this config setup? I would assume yes, unless the kernel itself is crashed.

It depends how 'hung' the system is. If the kernel is still alive and you have SysRq enabled, you can use whatever facility the terminal server offers to 'send break' to the serial console followed by the usual SysRq keys. So you can use that to collect process, memory and task information, and possibly to sync filesystem data to disk, attempt to unmount filesystems, and reboot the server.

Obviously if it is only unavailable due to network issues then you should be able to log in and do pretty much anything as usual.

This will also limit me to a console connection right after the point of the kernal loading after grub, correct?

Correct.

Annihilannic.