8.2.1 blkio Parameters

The following blkio parameters are defined:

blkio.io_merged

Reports the number of BIOS requests that have been merged into async, read, sync, or write I/O operations.

blkio.io_queued

Reports the number of requests for async, read, sync, or write I/O operations.

blkio.io_service_bytes

Reports the number of bytes transferred by async, read, sync, or write I/O operations to or from the devices specified by their major and minor numbers as recorded by the completely fair queueing (CFQ) scheduler, but not updated while it is operating on a request queue.

blkio.io_serviced

Reports the number of async, read, sync, or write I/O operations to or from the devices specified by their major and minor numbers as recorded by the CFQ scheduler, but not updated while it is operating on a request queue.

blkio.io_service_time

Reports the time in nanoseconds taken to complete async, read, sync, or write I/O operations to or from the devices specified by their major and minor numbers.

blkio.io_wait_time

Reports the total time in nanoseconds that a cgroup spent waiting for async, read, sync, or write I/O operations to complete to or from the devices specified by their major and minor numbers.

blkio.reset_stats

Resets the statistics for a cgroup if an integer is written to this parameter.

blkio.sectors

Reports the number of disk sectors written to or read from the devices specified by their major and minor numbers.

blkio.throttle.io_service_bytes

Reports the number of bytes transferred by async, read, sync, or write I/O operations to or from the devices specified by their major and minor numbers even while the CFQ scheduler is operating on a request queue.

blkio.throttle.io_serviced

Reports the number of async, read, sync, or write I/O operations to or from the devices specified by their major and minor numbers even while the CFQ scheduler is operating on a request queue.

blkio.throttle.read_bps_device

Specifies the maximum number of bytes per second that a cgroup may read from a device specified by its major and minor numbers. For example, the setting 8:1 4194304 specifies that a maximum of 4 MB per second may be read from /dev/sda1.

blkio.throttle.read_iops_device

Specifies the maximum number of read operations per second that a cgroup may perform on a device specified by its major and minor numbers. For example, the setting 8:1 100 specifies that a maximum of 100 read operations per second may be performed on/dev/sda1.

blkio.throttle.write_bps_device

Specifies the maximum number of bytes per second that a cgroup may write to a device specified by its major and minor numbers. For example, the setting 8:2 2097152 specifies a maximum of 2 MB per second may be written to /dev/sda2.

blkio.throttle.write_iops_device

Specifies the maximum number of write operations per second that a cgroup may perform on a device specified by its major and minor numbers. For example, the setting 8:2 50 specifies that a maximum of 50 write operations per second may be performed on /dev/sda2.

blkio.time

Reports the time in milliseconds that I/O access was available to a device specified by its major and minor numbers.

blkio.weight

Specifies a bias value from 100 to 1000 that determines a cgroup's share of access to block I/O. The default value is 1000. The value is overridden by the setting for an individual device (see blkio.weight_device).

blkio.weight_device

Specifies a bias value from 100 to 1000 that determines a cgroup's share of access to block I/O on a device specified by its major and minor numbers. For example, the setting 8:17 100 specifies a bias value of 100 for /dev/sdb1.