4:04 p.m.
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