QUESTION dahdi detected timeshift

[atsak]

I am experimenting with running PIAF under Hyper V, since the Windows 2012 hypervisor is free and can do a pretty neat replicate feature across the WAN (it's about 5 minutes behind but I bet this will be tolerated OK in practice) plus move VMs across servers without shared storage and useful odds and ends like that.

I got it to install fine (20643 and Green with 2.11 FPBX) but got a lot of dahdi detected timeshift errors on the console. I see some notes about using the independent_wallclock=1 setting as a boot option, but I'm not proficient enough with Linux to even know where to set a boot option - is it in grub.conf or ??? Can someone point me in the right direction?

I got rid of the error by going to webmin and then hardware/system time/options then setting "System supports hardware time" to No, but I have no idea what's going to happen when I try to make calls and so on, or use conferencing ,but one thing at a time. Is that the same thing as setting the independent wallclock boot option?

 

[Albert S]

I am running it on a physical machine and I am getting the same error.

I have 2 more PIAFs that don't do it. I don't know what's causing it.

 

[randy7376]

Albert S

The "time shift" message may be nothing to be overly concerned about unless you're having performance problems. I had a system a couple of years ago that did. Some of the issues I remember were paging didn't work properly, parking calls was hit and miss, conference room didn't work at all. The kicker was that NTP kept trying to re-correct the clock skew every three minutes.

This is what I ended up doing to alleviate the problems this system had.

First, does your motherboard BIOS support HPET? Check it and enable it if it's disabled. If not, it may still be supported if it shows up in available_clocksource, below.

Next, you can check what clock source your system is using.

cat /sys/devices/system/clocksource/clocksource0/current_clocksource

On the workstation I'm writing this from, mine returns tsc.

You can see what clock sources your system supports by doing the following:

cat /sys/devices/system/clocksource/clocksource0/available_clocksource

On the same system, I have tsc, hpet, and acpi_pm available.

You can switch the system clock source by using the following. For example, to set hpet:

echo hpet > /sys/devices/system/clocksource/clocksource0/current_clocksource

The change is immediate - no need to reboot. You can add clocksource=hpet as a boot option if you want hpet set each time you reboot. The system I had issues with would randomly choose tsc and hpet with tsc giving me nothing but grief. I added the kernel boot option and everything has been great ever since.

 

[randy7376]

atsak

You would add the independent_wallclock=1 to /boot/grub/grub.conf on the line for your current kernel that looks something like this:

kernel /vmlinuz-2.6.32-358.2.1.el6.i686 ro root=UUID=2a9f4cad-4bdc-41ca-b378-65586a9be758 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD

Just add your option to the end of the string. Use nano start it like this: nano -w . This will keep it from wrapping long lines around.

I'm not familiar with this kernel boot option, however. What was your source for that option? I get the same DAHDI time shift message when I run PIAF in VirtualBox. Thanks for anything you can pass along. It's too late right now. Else, I'd go look for it myself.

 

[atsak]

I googled . . . but it was a long time ago. Everything seems to be working fine even with the message so . . .

 

[randy7376]

atsak

I can confirm that independent_wallclock=1 doesn't do anything under VirtualBox. I still get the "time shift" message. Makes sense as everything I've come across indicates that this option is for Xen systems only.

So many kernel options, so little time...