Re: How to enter DDB through a terminal server / remote console ... ?
On Jun 28, 2006, at 6:28 PM, Robert Watson wrote: On Wed, 28 Jun 2006, User Freebsd wrote: 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm spending time with the remote tech today to get a serial console put online ... how do I drop into DDB remotely, where the serial console is going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, will work, will it? If configured to use a serial console (console=comconsole in loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the kernel config by sending a serial break. With my portmasters, I telnet to a TCP port to connect to the serial console, so I send a telnet break, using ^]send break. I *used* to set BREAK_TO_DEBUGGER also, but I discovered (the hard, painful, revenue-costing way) that if you ever power cycle a Cyclades TS1000 terminal server, it sends a break signal down each and every serial line attached to it. So, now I configure my debuggering in the kernel like this: # Kernel debugging options KDB #Enable the kernel debugger options KDB_TRACE options KDB_UNATTENDED # Enable the ddb debugger backend. options DDB # break on sequence CR ~ ^b options ALT_BREAK_TO_DEBUGGER This lets me get the best of both worlds. It is amazing that the CR ~ ^b sequence will respond even when the box itself is totally unresponsive due to some runaway process or other shortage of memory condition. Another thing you may wish to consider is adding option SW_WATCHDOG then running the watchdog daemon. It may help you by panicking your way out of deadlock automatically. You could also investigate getting a hardware watchdog card that works with watchdogd.
Re: How to enter DDB through a terminal server / remote console ... ?
On Wed, 28 Jun 2006, User Freebsd wrote: 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm spending time with the remote tech today to get a serial console put online ... how do I drop into DDB remotely, where the serial console is going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, will work, will it? If configured to use a serial console (console=comconsole in loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the kernel config by sending a serial break. With my portmasters, I telnet to a TCP port to connect to the serial console, so I send a telnet break, using ^]send break. Robert N M Watson Computer Laboratory University of Cambridge ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to enter DDB through a terminal server / remote console ... ?
On Wed, 28 Jun 2006, Robert Watson wrote: On Wed, 28 Jun 2006, User Freebsd wrote: 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm spending time with the remote tech today to get a serial console put online ... how do I drop into DDB remotely, where the serial console is going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, will work, will it? If configured to use a serial console (console=comconsole in loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the kernel config by sending a serial break. With my portmasters, I telnet to a TCP port to connect to the serial console, so I send a telnet break, using ^]send break. Have you ever had a problem with this warning: (useful for remote diagnostics, but also dangerous if you generate a spurious BREAK on the serial port!) in the handbook? Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email . [EMAIL PROTECTED] MSN . [EMAIL PROTECTED] Yahoo . yscrappy Skype: hub.orgICQ . 7615664 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to enter DDB through a terminal server / remote console ... ?
On Wed, Jun 28, 2006 at 07:34:43PM -0300, User Freebsd wrote: On Wed, 28 Jun 2006, Robert Watson wrote: On Wed, 28 Jun 2006, User Freebsd wrote: 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm spending time with the remote tech today to get a serial console put online ... how do I drop into DDB remotely, where the serial console is going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, will work, will it? If configured to use a serial console (console=comconsole in loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the kernel config by sending a serial break. With my portmasters, I telnet to a TCP port to connect to the serial console, so I send a telnet break, using ^]send break. Have you ever had a problem with this warning: (useful for remote diagnostics, but also dangerous if you generate a spurious BREAK on the serial port!) in the handbook? You can use ALT_BREAK_TO_DEBUGGER which uses the CR ~ ^b sequence if you are worried about stray breaks. Andrew ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to enter DDB through a terminal server / remote console ... ?
On Wed, 28 Jun 2006, User Freebsd wrote: On Wed, 28 Jun 2006, Robert Watson wrote: On Wed, 28 Jun 2006, User Freebsd wrote: 'k, now that I'm up to 3 6-STABLE servers that are deadlocking, I'm spending time with the remote tech today to get a serial console put online ... how do I drop into DDB remotely, where the serial console is going through a Portmaster Terminal server? issuing CTL-ALT-ESC, I doubt, will work, will it? If configured to use a serial console (console=comconsole in loader.conf), you can enter the debugger with BREAK_TO_DEBUGGER in the kernel config by sending a serial break. With my portmasters, I telnet to a TCP port to connect to the serial console, so I send a telnet break, using ^]send break. Have you ever had a problem with this warning: (useful for remote diagnostics, but also dangerous if you generate a spurious BREAK on the serial port!) in the handbook? Yes. It's unusual, but once in a while I get a nervous serial port. If you experience this, type Cont to continue, and then recompile your kernel with ALT_BREAK_TO_DEBUGGER but without BREAK_TO_DEBUGGER. Here's the notes entry: # Solaris implements a new BREAK which is initiated by a character # sequence CR ~ ^b which is similar to a familiar pattern used on # Sun servers by the Remote Console. options ALT_BREAK_TO_DEBUGGER I've not had problem a problem on any recent hardware except for my soekris. Robert N M Watson Computer Laboratory University of Cambridge ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to enter DDB through a terminal server / remote console ... ?
On Wed, Jun 28, 2006 at 11:57:58PM +0100, Robert Watson wrote: ... Yes. It's unusual, but once in a while I get a nervous serial port. If you experience this, type Cont to continue, and then recompile your kernel with ALT_BREAK_TO_DEBUGGER but without BREAK_TO_DEBUGGER. Here's the notes entry: I use the ALT_BREAK_TO_DEBUGGER here. -- - [EMAIL PROTECTED] http://www.db.net/~db ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to [EMAIL PROTECTED]
