ber_flush - Linux


The ber_flush command in Linux is used to flush buffers on a specific block device. It is primarily used to ensure that all data sent to a storage device is physically written to the media, preventing data loss in case of power outages or system crashes.


ber_flush [options] /dev/sd[a-z]


| Option/Flag | Description | Default Value |
| -a | Flush all buffers on the system | N/A |
| -d | Display the buffers that are being flushed | N/A |
| -e | Only flush dirty buffers | N/A |
| -f | Force flush even if the buffer is clean | N/A |
| -i [seconds] | Specify the interval (in seconds) between flushes | 5 |
| -o | Flush only the specified block device | N/A |
| -t | Test flush without actually performing it | N/A |


Flush buffers on a specific block device:

ber_flush /dev/sda

Flush all buffers on the system:

ber_flush -a

Flush dirty buffers every 10 seconds:

ber_flush -ie 10

Common Issues

  • Failed to flush buffers: Ensure that the specified block device has sufficient write permissions and is not mounted as read-only.

  • Buffers not being flushed: Check if the system is under heavy load or if there are other processes actively using the block device.


ber_flush can be integrated with other commands to improve performance and data integrity. For example, you can use sync before ber_flush to ensure that all data from user space is written to the block device before flushing the buffers.

Related Commands

  • sync: Synchronizes file system buffers to disk
  • fsync: Synchronizes a specific file to disk