Name
update
Synopsis
update [options
]
System administration command. update is a daemon that controls how often the kernel’s disk buffers are flushed to disk. update is also known as bdflush. The daemon forks a couple of processes to call system functions flush( ) and sync( ). When called by an unprivileged user, no daemon is created. Instead, update calls sync( ) and then exits. By default, update will wake up every 5 seconds and flush( ) some dirty buffers. If that doesn’t work, it will try waking up every 30 seconds to sync( ) the buffers to disk. Not all of the listed options are available in every version of update.
Options
- -d
Display the kernel parameters. This does not start the update daemon.
- -f seconds
Call flush( ) at this interval. Default is 5.
- -h
Help. Print a command summary.
- -s seconds
Call sync( ) at this interval. Default is 30.
- -0 percent
Flush buffers when the specified percent of the buffer cache is dirty.
- -1 blocks
The maximum number of dirty blocks to write out per wake cycle.
- -2 buffers
The number of clean buffers to try to obtain each time the free buffers are refilled.
- -3 blocks
Flush buffers if dirty blocks exceed blocks when trying to refill the buffers.
- -4 percent
Percent of buffer cache to scan when looking for free clusters.
- -5 seconds
Time for a data buffer to age before being flushed.
- -6 seconds
Time for a nondata buffer to age before being flushed.
- -7 constant
The time constant to use for load average.
- -8 ratio
How low the load average can be before ...
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