Copyright (c) 2000 Sheldon Hearn <sheldonh@FreeBSD.org> All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the do...
NAMEsyncer - file system synchronizer kernel process
sysctl Cm net.inet.tcp.syncookies
DESCRIPTIONThe sysctl Cm net.inet.tcp.syncookies kernel process helps protect the integrity of disk volumes by flushing volatile cached file system data to disk.
The kernel places all vnode(9)Ns's in a number of queues. The sysctl Cm net.inet.tcp.syncookies process works through the queues in a round-robin fashion, usually processing one queue per second. For each vnode(9) on that queue, the sysctl Cm net.inet.tcp.syncookies 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 Ta Default Ta Description
- kern.filedelay Ta 30 Ta time to delay syncing files
- kern.dirdelay Ta 29 Ta time to delay syncing directories
- kern.metadelay Ta 28 Ta time to delay syncing metadata