Since Linux kernel 2.6.35, you can increase the size of a pipe with the
F_SETPIPE_SZ fnctl(). Non-privileged users are limited to values between 0 and the current value of the
sysctl (1 MiB by default).
The value you use should be greater than 64 KiB and be a power of 2.
So you could do:
perl -MFcntl -e 'fcntl(STDIN, 1031, 1048576) or die $!' <> /dev/xconsole
(here with F_SETPIPE_SZ hardcoded to its value on my system as that Linux-specific
fcntl() is not otherwise available to my version of
Note that that
fcntl() doesn't affect
/dev/xconsole but the pipe buffer that has been instantiated when
/dev/xconsole was open (by
syslog and whatever application is reading the messages at the other end, so you'd need to do it at every boot after syslog has been started).
Now, whether that's what you should be doing is another matter. pipes are inter-process communication mechanism. They're not meant to store data. For syslog entries, 64 KiB should be more than enough as it's orders of magnitude greater than your typical log entry.
More likely in your case you've got a problem in that the application reading from
/dev/xconsole is not started early enough or is not reading fast enough.
In any case, I would advise against changing the global default pipe size.
That would be done by changing:
#define PIPE_DEF_BUFFERS 16
(expressed in number of 4 KiB pages) to something else in
include/linux/pipe_fs_i.h. It's not impossible that other things would need to be modified to reflect the change or that that change would affect other things in unexpected ways.
If you make it a power of 2 that is >= 16, it would be less likely to break things, but beware it may significantly affect global system performances and the scheduling behaviour in particular.