This is the help page for the new dminfo extension: ------------------------------------------------------------------- NAME dminfo - device mapper (dm) information SYNOPSIS dminfo [-b bio | -d | -l | -q | -s | -t] DESCRIPTION This command displays information about device-mapper mapped devices (dm devices). If no argument is entered, displays lists of existing dm devices. It's same as -l option. -b bio displays the information of the dm device which the bio is submitted in. If the bio isn't for dm devices, results will be error. -d displays dependency information for existing dm devices. -l displays lists of existing dm devices. -q displays queued I/O information for each target of existing dm devices. -s displays status information for each target of existing dm devices. -t displays table information for each target of existing dm devices. EXAMPLE Display lists of dm devices. "MAP_DEV" is the address of the struct mapped_device. "DM_TABLE" is the address of the struct dm_table. "TARGETS" is the number of targets which are in the struct dm_table. crash> dminfo MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 8 c4866c80 c4866280 1 vg0-snap0 253 6 f6a04a80 f6a04580 1 vg0-lv0-real 253 0 c4840380 c4841880 1 mp0 253 5 f7c50c80 c488e480 1 via_cbeheddbdd 253 7 c4866a80 c4866380 1 vg0-snap0-cow 253 4 d441e280 c919ed80 1 dummy1 253 3 f5dc4280 cba81d80 1 dummy0 253 2 f7c53180 c4866180 1 vg0-lv0 253 1 f746d280 f746cd80 1 mp0p1 Display the dm device information which the bio is submitted in. The bio (ceacee80) is a clone of the bio (ceacee00) which is submitted in the dm-3 (dummy0). And the bio (ceacee00) is a clone of the bio (ceaced80) which is submitted in the dm-4 (dummy1), too. The bio (ceaced80) is the original bio. crash> dminfo -b ceacee80 DM_BIO_ADDRESS MAJ MIN MAP_DEV DEVNAME ceacee00 253 3 f5dc4280 dm-3 crash> dminfo -b ceacee00 DM_BIO_ADDRESS MAJ MIN MAP_DEV DEVNAME ceaced80 253 4 d441e280 dm-4 crash> dminfo -b ceaced80 dminfo: invalid kernel virtual address: 64 type: "GET_VALUE: dm_io.bio" Display dependency information for each target. The vg0-snap0 depends on thd dm-6 (vg0-lv0-real) and the dm-7 (vg0-snap0-cow) crash> dminfo -d MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 8 c4866c80 c4866280 1 vg0-snap0 MAJ MIN GENDISK COUNT DEVNAME 253 7 c4866980 1 dm-7 253 6 f6a04280 1 dm-6 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 6 f6a04a80 f6a04580 1 vg0-lv0-real MAJ MIN GENDISK COUNT DEVNAME 8 0 f7f24c80 1 sda MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 7 c4866a80 c4866380 1 vg0-snap0-cow MAJ MIN GENDISK COUNT DEVNAME 8 0 f7f24c80 1 sda MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 2 f7c53180 c4866180 1 vg0-lv0 MAJ MIN GENDISK COUNT DEVNAME 253 6 f6a04280 1 dm-6 Display queued I/O information for each target. The information is displayed under the "PRIVATE_DATA" column. crash> dminfo -q MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 5 f7c50c80 c488e480 1 via_cbeheddbdd TARGET TARGET_TYPE PRIVATE_DATA f8961080 mirror (reads) (writes) (quiesced) (recovered) -------------------------------------------------------------- "reads/writes" are members of the struct mirror_set, and "quiesced/recovered" are members of the struct region_hash. If the list is empty, the member is bracketed by "()". -------------------------------------------------------------- MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 0 c4840380 c4841880 1 mp0 TARGET TARGET_TYPE PRIVATE_DATA f8802080 multipath queue_size:0 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 1 f746d280 f746cd80 1 mp0p1 TARGET TARGET_TYPE PRIVATE_DATA f8821080 linear No queue info Display status information for each target. The information is displayed under the "PRIVATE_DATA" column. crash> dminfo -s MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 0 c4840380 c4841880 1 mp0 TARGET TARGET_TYPE PRIVATE_DATA f8802080 multipath queue_if_no_path:0 hwh:none nr_pgs:1 PG PG_STATUS NR_PATHS PATHS 1 active 2 8:16(A,0) 8:32(A,0) -------------------------------------------------------------- Format of "PATHS": <major>:<minor>(<status>,<fail_count>) Status: A:active, F:faulty Fail_count: the value of the struct pgpath.fail_count -------------------------------------------------------------- MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 5 f7c50c80 c488e480 1 via_cbeheddbdd TARGET TARGET_TYPE PRIVATE_DATA f8961080 mirror in_sync:1 dev:8:16(A,0),8:32(A,0) -------------------------------------------------------------- Format of "dev": <major>:<minor>(<status>,<error_count>) Status: A:active, D:degraded Error_count: the value of the struct mirror.error_count -------------------------------------------------------------- MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 1 f746d280 f746cd80 1 mp0p1 TARGET TARGET_TYPE PRIVATE_DATA f8821080 linear No status info Display table information for each target. The information is displayed under the "PRIVATE_DATA" column. crash> dminfo -t MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 8 c4866c80 c4866280 1 vg0-snap0 TARGET TARGET_TYPE PRIVATE_DATA f89b4080 snapshot orig:253:6 cow:253:7 type:P chunk_size:16 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 6 f6a04a80 f6a04580 1 vg0-lv0-real TARGET TARGET_TYPE PRIVATE_DATA f890f080 linear begin:0 len:204800 dev:8:5 offset:384 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 0 c4840380 c4841880 1 mp0 TARGET TARGET_TYPE PRIVATE_DATA f8802080 multipath queue_if_no_path:0 hwh:none nr_pgs:1 PG PATH_SELECTOR NR_PATHS PATHS 1 round-robin 2 8:16 8:32 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 5 f7c50c80 c488e480 1 via_cbeheddbdd TARGET TARGET_TYPE PRIVATE_DATA f8961080 mirror log:core dev:8:16(0),8:32(0) -------------------------------------------------------------- Format of "dev": <major>:<minor>(<offset>) Offset: the value of the struct mirror.offset -------------------------------------------------------------- MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 7 c4866a80 c4866380 1 vg0-snap0-cow TARGET TARGET_TYPE PRIVATE_DATA f899d080 linear begin:0 len:8192 dev:8:5 offset:205184 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 2 f7c53180 c4866180 1 vg0-lv0 TARGET TARGET_TYPE PRIVATE_DATA f8bbc080 snapshot-origin orig_dev:253:6 MAJ MIN MAP_DEV DM_TABLE TARGETS MAPNAME 253 1 f746d280 f746cd80 1 mp0p1 TARGET TARGET_TYPE PRIVATE_DATA f8821080 linear begin:0 len:2040192 dev:253:0 offset:63