1What: /sys/block/dm-<num>/dm/name 2Date: January 2009 3KernelVersion: 2.6.29 4Contact: dm-devel@redhat.com 5Description: Device-mapper device name. 6 Read-only string containing mapped device name. 7Users: util-linux, device-mapper udev rules 8 9What: /sys/block/dm-<num>/dm/uuid 10Date: January 2009 11KernelVersion: 2.6.29 12Contact: dm-devel@redhat.com 13Description: Device-mapper device UUID. 14 Read-only string containing DM-UUID or empty string 15 if DM-UUID is not set. 16Users: util-linux, device-mapper udev rules 17 18What: /sys/block/dm-<num>/dm/suspended 19Date: June 2009 20KernelVersion: 2.6.31 21Contact: dm-devel@redhat.com 22Description: Device-mapper device suspend state. 23 Contains the value 1 while the device is suspended. 24 Otherwise it contains 0. Read-only attribute. 25Users: util-linux, device-mapper udev rules 26 27What: /sys/block/dm-<num>/dm/rq_based_seq_io_merge_deadline 28Date: March 2015 29KernelVersion: 4.1 30Contact: dm-devel@redhat.com 31Description: Allow control over how long a request that is a 32 reasonable merge candidate can be queued on the request 33 queue. The resolution of this deadline is in 34 microseconds (ranging from 1 to 100000 usecs). 35 Setting this attribute to 0 (the default) will disable 36 request-based DM's merge heuristic and associated extra 37 accounting. This attribute is not applicable to 38 bio-based DM devices so it will only ever report 0 for 39 them. 40 41What: /sys/block/dm-<num>/dm/use_blk_mq 42Date: March 2015 43KernelVersion: 4.1 44Contact: dm-devel@redhat.com 45Description: Request-based Device-mapper blk-mq I/O path mode. 46 Contains the value 1 if the device is using blk-mq. 47 Otherwise it contains 0. Read-only attribute. 48