Gentle readers,
I am trying to observe system behavior on our RHEL 5.2 machines. I notice that, it appears to me, based on random iterations of
...that if the pdflush is flushing buffers at the time of my write, my write will take about as long as
This indicates to me that pdflush blocks all write()'s until the flush to disk is complete. The question is: am I correct?
Most of the time, the first dd (without the sync) is much faster than the second. By watching /proc/meminfo, I am able to see approximately when the sync initiated by pdflush takes place. This would be every 30 seconds, as my machine is not filling the disk buffers very quickly. We're talking only a few hundred kilobytes every 30 seconds.
Hi everyone,
Ive got a quick question about the feasibility and any suggestions for a shell script. I can use sh or ksh, doesnt matter. Basically, Ive got an output file from a db2 command that looks like so:
SCHEMA NAME CARD LEAF ELEAF LVLS ISIZE NDEL KEYS F4 F5 ... (3 Replies)
Hi all....I have a Sun Ultra2 that I want to use with my PC monitor. I have purchased an adapter that does not work and I was told I need to change my video card setting (if I can) to Separate Sync.....my Monitor product number ends in 1343......I am running SunOS 5.7 ......anyone have any ideas?
... (0 Replies)
I found this logging subroutine on the net that I want to use but despite trying many things, I cannot figure out how to get the date in front of the logged text. Ideally what I'm looking for is a line that looks something like this:
Wed Aug 20 18:17:29 PDT 2008 - my logging info here.
my... (2 Replies)
Hey guys
First post... and im not exactly a solaris guru but here goes
Ive setup a solaris 10 box with a raidz2 set of 6 disks...
I have also setup Samba with open shares for some CIFs access...
now my issue is that when i transfer large files to it the network performance contantly... (8 Replies)
Hi
I am looking for an easy way to lock game mode (0) for everyone included op on a Minecraft server. It can be a script that every time a player changes game to 1 the script changes back to 0. What the player writes is visible in the java console. I am not good at script programming and my... (0 Replies)
I have a custom auditing class configured for these events but it doesn't seem to be catching it when I do a "echo hey > test.txt" Any ideas on why that is?
---------- Post updated at 06:04 PM ---------- Previous update was at 05:47 PM ----------
Scratch this topic, it looks like it's because... (0 Replies)
Discussion started by: thmnetwork
0 Replies
LEARN ABOUT CENTOS
bdflush
BDFLUSH(2) Linux Programmer's Manual BDFLUSH(2)NAME
bdflush - start, flush, or tune buffer-dirty-flush daemon
SYNOPSIS
#include <sys/kdaemon.h>
int bdflush(int func, long *address);
int bdflush(int func, long data);
DESCRIPTION
Note: Since Linux 2.6, this system call is deprecated and does nothing. It is likely to disappear altogether in a future kernel release.
Nowadays, the task performed by bdflush() is handled by the kernel pdflush thread.
bdflush() starts, flushes, or tunes the buffer-dirty-flush daemon. Only a privileged process (one with the CAP_SYS_ADMIN capability) may
call bdflush().
If func is negative or 0, and no daemon has been started, then bdflush() enters the daemon code and never returns.
If func is 1, some dirty buffers are written to disk.
If func is 2 or more and is even (low bit is 0), then address is the address of a long word, and the tuning parameter numbered (func-2)/2
is returned to the caller in that address.
If func is 3 or more and is odd (low bit is 1), then data is a long word, and the kernel sets tuning parameter numbered (func-3)/2 to that
value.
The set of parameters, their values, and their valid ranges are defined in the Linux kernel source file fs/buffer.c.
RETURN VALUE
If func is negative or 0 and the daemon successfully starts, bdflush() never returns. Otherwise, the return value is 0 on success and -1
on failure, with errno set to indicate the error.
ERRORS
EBUSY An attempt was made to enter the daemon code after another process has already entered.
EFAULT address points outside your accessible address space.
EINVAL An attempt was made to read or write an invalid parameter number, or to write an invalid value to a parameter.
EPERM Caller does not have the CAP_SYS_ADMIN capability.
CONFORMING TO
bdflush() is Linux-specific and should not be used in programs intended to be portable.
SEE ALSO fsync(2), sync(2), sync(8), update(8)COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2012-03-05 BDFLUSH(2)