http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/networking/netconsole.txt;h=3c2f2b3286385337ce5ec24afebd4699dd1e6e0a;hb=HEAD
netconsole is a facility to capture oops traces. It is not a console per se and does not require a head/gtk/x11 etc to work. The link above explains the usage, etc. mike wrote: > Well these are headless production servers, CLI only. no GTK, no X11. > also I am not running the newer kernels (and I can't...) it looks like > I cannot run a hybrid of 2.6.24-16 and 2.6.22-19, whichever one has > mounted the drive first is the winner. > > If I mix them, I can get the 2.6.24's to mount, then the older ones > give the "number too large" error or whatever. So I can't currently > use one server on my cluster to test because it would require > upgrading all of them just for this test. > > On 4/21/08, Sunil Mushran <[EMAIL PROTECTED]> wrote: > >> Setting up netconsole does not require a reboot. The idea is to >> catch the oops trace when the oops happens. Without that trace, >> we are flying blind. >> >> >> mike wrote: >> >>> Since these are production I can't do much. >>> >>> But I did get an error (it's not happening as much but it still blips >>> here and there) >>> >>> Notice that /dev/sdb (my iscsi target using ocfs2) hits 0.00% >>> utilization, 3 seconds before my proxy says "hey, timeout" - every >>> other second there is -always- some utilization going on. >>> >>> What could be steps to figure out this issue? Using debugfs.ocfs2 or >>> >> something? >> >>> It's mounted as: >>> /dev/sdb1 on /home type ocfs2 >>> (rw,_netdev,noatime,data=writeback,heartbeat=local) >>> >>> I know I'm not being much help, but I'm willing to try almost anything >>> as long as it doesn't cause downtime or require cluster-wide changes >>> (since those require downtime...) - I want to try to go back to >>> 2.6.24-16 with data=writeback and see if that fixes the crashing >>> issue, but if I'm having issues already like this perhaps I should >>> resolve this before moving up. >>> >>> >>> >>> [EMAIL PROTECTED] ~]# cat /root/web03-iostat.txt >>> >>> Time: 02:11:46 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 3.71 0.00 27.23 8.91 0.00 60.15 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 54.46 0.00 309.90 0.00 2914.85 >>> 9.41 23.08 74.47 0.93 28.71 >>> sdb 12.87 0.00 17.82 0.00 245.54 0.00 >>> 13.78 0.33 17.78 18.33 32.67 >>> >>> Time: 02:11:47 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.25 0.00 26.24 2.23 0.00 71.29 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 0.00 0.00 0.00 0.00 0.00 >>> 0.00 0.00 0.00 0.00 0.00 >>> sdb 5.94 0.00 22.77 0.99 228.71 0.99 >>> 9.67 0.42 17.92 17.08 40.59 >>> >>> Time: 02:11:48 PM <- THIS HAS THE ISSUE >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.00 0.00 25.99 0.00 0.00 74.01 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 10.89 0.00 2.97 0.00 110.89 >>> 37.33 0.00 0.00 0.00 0.00 >>> sdb 0.00 0.00 0.00 0.00 0.00 0.00 >>> 0.00 0.00 0.00 0.00 0.00 >>> >>> >>> Time: 02:11:49 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.25 0.00 14.85 0.99 0.00 83.91 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 0.00 0.00 0.00 0.00 0.00 >>> 0.00 0.00 0.00 0.00 0.00 >>> sdb 0.99 0.00 2.97 0.99 30.69 0.99 >>> 8.00 0.07 17.50 17.50 6.93 >>> >>> Time: 02:11:50 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.74 0.00 1.24 1.73 0.00 96.29 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 0.00 0.00 0.00 0.00 0.00 >>> 0.00 0.00 0.00 0.00 0.00 >>> sdb 0.99 0.00 5.94 0.00 55.45 0.00 >>> 9.33 0.07 11.67 11.67 6.93 >>> >>> Time: 02:11:51 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.00 0.00 1.24 16.34 0.00 82.43 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 153.47 0.00 494.06 0.00 5156.44 >>> 10.44 55.62 107.23 1.16 57.43 >>> sdb 2.97 0.00 11.88 0.99 117.82 0.99 >>> 9.23 0.26 13.08 20.00 25.74 >>> >>> Time: 02:11:52 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.00 0.00 0.25 3.22 0.00 96.53 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 0.00 0.00 16.83 0.00 158.42 >>> 9.41 0.13 164.71 1.18 1.98 >>> sdb 1.98 0.00 2.97 0.00 39.60 0.00 >>> 13.33 0.13 73.33 43.33 12.87 >>> >>> Time: 02:11:53 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 0.50 0.00 0.25 4.70 0.00 94.55 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 0.00 0.00 0.00 0.00 0.00 >>> 0.00 0.00 0.00 0.00 0.00 >>> sdb 5.94 0.00 11.88 0.99 141.58 0.99 >>> 11.08 0.20 15.38 15.38 19.80 >>> >>> Time: 02:11:54 PM >>> avg-cpu: %user %nice %system %iowait %steal %idle >>> 3.96 0.00 10.15 0.74 0.00 85.15 >>> >>> Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s >>> avgrq-sz avgqu-sz await svctm %util >>> sda 0.00 20.79 0.00 4.95 0.00 205.94 >>> 41.60 0.00 0.00 0.00 0.00 >>> sdb 4.95 0.00 5.94 0.00 87.13 0.00 >>> 14.67 0.07 11.67 11.67 6.93 >>> >>> >>> >>> On 4/21/08, Sunil Mushran <[EMAIL PROTECTED]> wrote: >>> >>> >>> >>>> Do you have the panic output... kernel stack trace. We'll need >>>> that to figure this out. Without that, we can only speculate. >>>> >>>> mike wrote: >>>> >>>> >>>> >>>>> On 4/21/08, Tao Ma <[EMAIL PROTECTED]> wrote: >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>> mike wrote: >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> I have changed my kernel back to 2.6.22-14-server, and now I don't >>>>>>> >> get >> >>>>>>> the kernel panics. It seems like an issue with 2.6.24-16 and some >>>>>>> >> i/o >> >>>>>>> made it crash... >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> OK, so it seems that it is a bug for ocfs2 kernel, not the >>>>>> >> ocfs2-tools. >> >>>>>> >>>> :) >>>> >>>> >>>> >>>>>> Then could you please describe it in more detail about how the >>>>>> >> kernel >> >>>>>> >>>> panic >>>> >>>> >>>> >>>>>> happens? >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> Yeah, this specific issue seems like a kernel issue. >>>>> >>>>> I don't know, these are production systems and I am already getting >>>>> angry customers. I can't really test anymore. Both are standard Ubuntu >>>>> kernels. >>>>> >>>>> Okay: 2.6.22-14-server (I think still minor file access issues) >>>>> Breaks under load: 2.6.24-16-server >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>>> However I am still getting file access timeouts once in a while. I >>>>>>> >> am >> >>>>>>> nervous about putting more load on the setup. >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> Also please provide more details about it. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> I am using nginx for a frontend load balancer, and nginx for a >>>>> webserver as well. This doesn't seem to be related to the webserver at >>>>> all though, it was happening before this. >>>>> >>>>> lvs01 proxies traffic in to web01, web02, and web03 (currently using >>>>> nginx, before I was using LVS/ipvsadm) >>>>> >>>>> Every so often, one of the webservers sends me back >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>>>> [EMAIL PROTECTED] .batch]# cat /etc/default/o2cb >>>>>>> >>>>>>> # O2CB_ENABLED: 'true' means to load the driver on boot. >>>>>>> O2CB_ENABLED=true >>>>>>> >>>>>>> # O2CB_BOOTCLUSTER: If not empty, the name of a cluster to start. >>>>>>> O2CB_BOOTCLUSTER=mycluster >>>>>>> >>>>>>> # O2CB_HEARTBEAT_THRESHOLD: Iterations before a node is considered >>>>>>> >>>>>>> >>>>>>> >>>> dead. >>>> >>>> >>>> >>>>>>> O2CB_HEARTBEAT_THRESHOLD=7 >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> This value is a little smaller, so how did you build up your shared >>>>>> disk(iSCSI or ...)? The most common value I heard of is 61. It is >>>>>> >> about >> >>>>>> >>>> 120 >>>> >>>> >>>> >>>>>> secs. I don't know the reason and maybe Sunil can tell you. ;) >>>>>> You can also refer to >>>>>> >>>>>> >>>>>> >>>>>> >> http://oss.oracle.com/projects/ocfs2/dist/documentation/ocfs2_faq.html#TIMEOUT. >> >>>> >>>>>> >>>>>> >>>>>>> # O2CB_IDLE_TIMEOUT_MS: Time in ms before a network connection is >>>>>>> considered dead. >>>>>>> O2CB_IDLE_TIMEOUT_MS=10000 >>>>>>> >>>>>>> # O2CB_KEEPALIVE_DELAY_MS: Max time in ms before a keepalive >>>>>>> >> packet is >> >>>>>>> >>>>>>> >>>>>>> >>>>>> sent >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>> O2CB_KEEPALIVE_DELAY_MS=5000 >>>>>>> >>>>>>> # O2CB_RECONNECT_DELAY_MS: Min time in ms between connection >>>>>>> >> attempts >> >>>>>>> O2CB_RECONNECT_DELAY_MS=2000 >>>>>>> >>>>>>> >>>>>>> On 4/21/08, Tao Ma <[EMAIL PROTECTED]> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> Hi Mike, >>>>>>>> Are you sure it is caused by the update of ocfs2-tools? >>>>>>>> AFAIK, the ocfs2-tools only include tools like mkfs, fsck and >>>>>>>> >> tunefs >> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> etc. So >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> if you don't make any change to the disk(by using this new >>>>>>>> >> tools), >> >>>>>>>> >>>> it >>>> >>>> >>>> >>>>>>>> shouldn't cause the problem of kernel panic since they are all >>>>>>>> >> user >> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> space >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> tools. >>>>>>>> Then there is only one thing maybe. Have you modify >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> /etc/sysconfig/o2cb(This >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> is the place for RHEL, not sure the place in ubuntu)? I have >>>>>>>> >> checked >> >>>>>>>> >>>> the >>>> >>>> >>>> >>>>>>>> >>>>>> rpm >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> package for RHEL, it will update /etc/sysconfig/o2cb and this >>>>>>>> >> file >> >>>>>>>> >>>> has >>>> >>>> >>>> >>>>>>>> >>>>>> some >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> timeouts defined in it. >>>>>>>> So do you have some backups for this file? If yes, please >>>>>>>> >> restore it >> >>>>>>>> >>>> to >>>> >>>> >>>> >>>>>>>> >>>>>> see >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> whether it helps(I can't say it for sure). >>>>>>>> If not, do you remember the old value of some timeouts you set >>>>>>>> >> for >> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> ocfs2? If >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>>>> yes, you can use o2cb configure to set them by yourself. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>> >>>>> _______________________________________________ >>>>> Ocfs2-users mailing list >>>>> [email protected] >>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-users >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>> _______________________________________________ >>> Ocfs2-users mailing list >>> [email protected] >>> http://oss.oracle.com/mailman/listinfo/ocfs2-users >>> >>> >>> >> _______________________________________________ Ocfs2-users mailing list [email protected] http://oss.oracle.com/mailman/listinfo/ocfs2-users
