[DRBD-user] Re: drbd 0.7.21(kernel 2.6.17) hang problem - SOLVED

[Maciej Bogucki]

>>>>When I only leave one node(primary) I still have laga. And it is
>>>>strangest thing to me.  It is x86_64 HA Cluster, but I have the same
>>>>hardware in another location and there are no problems. Strange :)
>>>
>>>right. so I'll file that as "somebody elses problem",
>>>as it seems not to be drbd problem.
>>
>>We have changed almost everything.
>>1. have tested kernels from 2.6.14 to 2.6.17
>>2. drbd from 0.7.14 to 0.7.21
>>3. changed machine to different vendor
>>4. changed SCSI disks to IDE
>>5. changed x86_46 architecture to i386
>>And all fail. All the time we get console lags.
>>The strangest thing is that when we run mysql on phisical
>>device(/dev/sdaX) there is no lags.
>>I don't know how can I debug it.
> 
> 
> I'm certainly not an expert in reading those kernel traces, but even for 
> non-kernel hackers it may give an idea whats going on. Also, the nice linbit 
> people certainly know how to read it.
> 
> One can get a trace of the current tasks via 'sysrq t' , 
> see /usr/src/linux/Documentation/sysrq.txt for details.

Hello,

Thank You verry much for Your help. The problem was trivial and it 
wasn't drbd. It was heartbeat, exactly we set

SERVICE_RUN_NICE_LEVEL="-12"

in /etc/sysconfig/heartbeat and mysql consumed all resoures, and we got 
lags.

Best Regards
Maciej Bogucki