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Diffstat (limited to 'Documentation/networking/netconsole.txt')
| -rw-r--r-- | Documentation/networking/netconsole.txt | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt index 1caa6c734691..5962f45815a2 100644 --- a/Documentation/networking/netconsole.txt +++ b/Documentation/networking/netconsole.txt | |||
| @@ -44,11 +44,36 @@ WARNING: the default target ethernet setting uses the broadcast | |||
| 44 | ethernet address to send packets, which can cause increased load on | 44 | ethernet address to send packets, which can cause increased load on |
| 45 | other systems on the same ethernet segment. | 45 | other systems on the same ethernet segment. |
| 46 | 46 | ||
| 47 | TIP: some LAN switches may be configured to suppress ethernet broadcasts | ||
| 48 | so it is advised to explicitly specify the remote agents' MAC addresses | ||
| 49 | from the config parameters passed to netconsole. | ||
| 50 | |||
| 51 | TIP: to find out the MAC address of, say, 10.0.0.2, you may try using: | ||
| 52 | |||
| 53 | ping -c 1 10.0.0.2 ; /sbin/arp -n | grep 10.0.0.2 | ||
| 54 | |||
| 55 | TIP: in case the remote logging agent is on a separate LAN subnet than | ||
| 56 | the sender, it is suggested to try specifying the MAC address of the | ||
| 57 | default gateway (you may use /sbin/route -n to find it out) as the | ||
| 58 | remote MAC address instead. | ||
| 59 | |||
| 47 | NOTE: the network device (eth1 in the above case) can run any kind | 60 | NOTE: the network device (eth1 in the above case) can run any kind |
| 48 | of other network traffic, netconsole is not intrusive. Netconsole | 61 | of other network traffic, netconsole is not intrusive. Netconsole |
| 49 | might cause slight delays in other traffic if the volume of kernel | 62 | might cause slight delays in other traffic if the volume of kernel |
| 50 | messages is high, but should have no other impact. | 63 | messages is high, but should have no other impact. |
| 51 | 64 | ||
| 65 | NOTE: if you find that the remote logging agent is not receiving or | ||
| 66 | printing all messages from the sender, it is likely that you have set | ||
| 67 | the "console_loglevel" parameter (on the sender) to only send high | ||
| 68 | priority messages to the console. You can change this at runtime using: | ||
| 69 | |||
| 70 | dmesg -n 8 | ||
| 71 | |||
| 72 | or by specifying "debug" on the kernel command line at boot, to send | ||
| 73 | all kernel messages to the console. A specific value for this parameter | ||
| 74 | can also be set using the "loglevel" kernel boot option. See the | ||
| 75 | dmesg(8) man page and Documentation/kernel-parameters.txt for details. | ||
| 76 | |||
| 52 | Netconsole was designed to be as instantaneous as possible, to | 77 | Netconsole was designed to be as instantaneous as possible, to |
| 53 | enable the logging of even the most critical kernel bugs. It works | 78 | enable the logging of even the most critical kernel bugs. It works |
| 54 | from IRQ contexts as well, and does not enable interrupts while | 79 | from IRQ contexts as well, and does not enable interrupts while |