protocol for transmitting kernel dumps to a remote
To compile netdump client support into the kernel, place the following line in
your kernel configuration file:
netdump is a UDP-based protocol for transmitting kernel dumps to a remote host.
A netdump client is a panicking kernel, and a netdump server is a host running
daemon, available in ports as
clients are configured using the
client messages consist of a
fixed-size header followed by a variable-sized payload. The header contains
the message type, a sequence number, the offset of the payload data in the
kernel dump, and the length of the payload data (not including the header).
The message types are
server messages have a fixed size
and contain only the sequence number of the client message. These messages
indicate that the server has successfully processed the client message with
the corresponding sequence number. All client messages are acknowledged this
way. Server messages are always sent to port 20024 of the client.
To initiate a
, the client sends a
message to the server at port 20023.
The client may include a relative path in its payload, in which case the
server should attempt to save the
dump at that path relative to its configured dump directory. The server will
using a random
source port, and the client must send all subsequent messages to that port.
message payloads contain the
kernel dump header, dump contents, and dump encryption key respectively. The
offset in the message header should be treated as a seek offset in the
corresponding file. There are no ordering requirements for these messages.
is completed by sending the
message to the server.
The following network drivers support netdump:
The following variables are available as both
- Control debug message verbosity. Debug messages are disabled by default,
but are useful when troubleshooting or when developing driver
- Specify a path relative to the server's dump directory in which to store
the dump. For example, if the
server is configured to store dumps in
/var/crash, a path of
“foo” will cause the server to attempt to store dumps from
the client in /var/crash/foo. The
server will not automatically create the relative directory.
client support first appeared in
Only IPv4 is supported.
may only be used after the kernel has