| What: /sys/block/dm-<num>/dm/name | |
| Date: January 2009 | |
| KernelVersion: 2.6.29 | |
| Contact: dm-devel@redhat.com | |
| Description: Device-mapper device name. | |
| Read-only string containing mapped device name. | |
| Users: util-linux, device-mapper udev rules | |
| What: /sys/block/dm-<num>/dm/uuid | |
| Date: January 2009 | |
| KernelVersion: 2.6.29 | |
| Contact: dm-devel@redhat.com | |
| Description: Device-mapper device UUID. | |
| Read-only string containing DM-UUID or empty string | |
| if DM-UUID is not set. | |
| Users: util-linux, device-mapper udev rules | |
| What: /sys/block/dm-<num>/dm/suspended | |
| Date: June 2009 | |
| KernelVersion: 2.6.31 | |
| Contact: dm-devel@redhat.com | |
| Description: Device-mapper device suspend state. | |
| Contains the value 1 while the device is suspended. | |
| Otherwise it contains 0. Read-only attribute. | |
| Users: util-linux, device-mapper udev rules | |
| What: /sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline | |
| Date: March 2015 | |
| KernelVersion: 4.1 | |
| Contact: dm-devel@redhat.com | |
| Description: Allow control over how long a request that is a | |
| reasonable merge candidate can be queued on the request | |
| queue. The resolution of this deadline is in | |
| microseconds (ranging from 1 to 100000 usecs). | |
| Setting this attribute to 0 (the default) will disable | |
| request-based DM's merge heuristic and associated extra | |
| accounting. This attribute is not applicable to | |
| bio-based DM devices so it will only ever report 0 for | |
| them. | |
| What: /sys/block/dm-<num>/dm/use_blk_mq | |
| Date: March 2015 | |
| KernelVersion: 4.1 | |
| Contact: dm-devel@redhat.com | |
| Description: Request-based Device-mapper blk-mq I/O path mode. | |
| Contains the value 1 if the device is using blk-mq. | |
| Otherwise it contains 0. Read-only attribute. |