SYNCER(4) BSD Kernel Interfaces Manual SYNCER(4)NAME
syncer -- file system synchronizer kernel process
SYNOPSIS
syncer
DESCRIPTION
The syncer kernel process helps protect the integrity of disk volumes by flushing volatile cached file system data to disk.
The kernel places all vnode(9)'s in a number of queues. The syncer process works through the queues in a round-robin fashion, usually pro-
cessing one queue per second. For each vnode(9) on that queue, the syncer process forces a write out to disk of its dirty buffers.
The usual delay between the time buffers are dirtied and the time they are synced is controlled by the following sysctl(8) tunable variables:
Variable Default Description
kern.filedelay 30 time to delay syncing files
kern.dirdelay 29 time to delay syncing directories
kern.metadelay 28 time to delay syncing metadata
SEE ALSO sync(2), fsck(8), sync(8), sysctl(8)HISTORY
The syncer process is a descendant of the 'update' command, which appeared in Version 6 AT&T UNIX, and was usually started by /etc/rc when
the system went multi-user. A kernel initiated 'update' process first appeared in FreeBSD 2.0.
BUGS
It is possible on some systems that a sync(2) occurring simultaneously with a crash may cause file system damage. See fsck(8).
BSD July 14, 2000 BSD
Check Out this Related Man Page
VOP_FSYNC(9) BSD Kernel Developer's Manual VOP_FSYNC(9)NAME
VOP_FSYNC -- flush file system buffers for a file
SYNOPSIS
#include <sys/param.h>
#include <sys/vnode.h>
int
VOP_FSYNC(struct vnode *vp, int waitfor, struct thread *td);
DESCRIPTION
This call flushes any dirty file system buffers for the file. It is used to implement the sync(2) and fsync(2) system calls.
Its arguments are:
vp The vnode of the file.
waitfor Whether the function should wait for I/O to complete. Possible values are:
MNT_WAIT Synchronously wait for I/O to complete.
MNT_NOWAIT Start all I/O, but do not wait for it.
MNT_LAZY Push data not written by file system syncer.
td The calling thread.
The argument waitfor is either MNT_WAIT or MNT_NOWAIT and specifies whether or not the function should wait for the writes to finish before
returning.
LOCKS
The file should be locked on entry.
RETURN VALUES
Zero is returned if the call is successful, otherwise an appropriate error code is returned.
ERRORS
[ENOSPC] The file system is full.
[EDQUOT] Quota exceeded.
SEE ALSO vnode(9)AUTHORS
This manual page was written by Doug Rabson.
BSD July 24, 1996 BSD
Hi,
May I pls. know what would be the equivalent kernel parameter in HP-UX for the below Linux kernel parameter.
sysctl kern.ps_showallprocs - This setting in Linux would let users see their own processes in "ps".
Thanks,
Narasimha (1 Reply)
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