Public bug reported:
We are trying to activate the active/active configuration in multipathd,
for 2 paths between an AMS2100 array and a Ubuntu 12.04 Server.
We set "prio const" in /etc/multipath.conf. After starting the multipath
daemon, we observe the following:
a) # multipath -ll
mpath0 (360060e80104dac0004f349c800000000) dm-0 HITACHI,DF600F
size=100G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 8:0:0:0 sdc 8:32 active ready running
`-+- policy='round-robin 0' prio=0 status=enabled
`- 7:0:0:0 sdb 8:16 active ready running
Paths have different priorities.
b) multipath -v4
Jun 15 16:39:01 | sdb: not found in pathvec
Jun 15 16:39:01 | sdb: mask = 0x1f
Jun 15 16:39:01 | sdb: dev_t = 8:16
Jun 15 16:39:01 | sdb: size = 209715200
Jun 15 16:39:01 | sdb: subsystem = scsi
Jun 15 16:39:01 | sdb: vendor = HITACHI
Jun 15 16:39:01 | sdb: product = DF600F
Jun 15 16:39:01 | sdb: rev = 0000
Jun 15 16:39:01 | sdb: h:b:t:l = 7:0:0:0
Jun 15 16:39:01 | sdb: serial = 830530000000
Jun 15 16:39:01 | sdb: get_state
Jun 15 16:39:01 | loading /lib/multipath/libchecktur.so checker
Jun 15 16:39:01 | sdb: path checker = tur (controller setting)
Jun 15 16:39:01 | sdb: state = running
Jun 15 16:39:01 | sdb: state = 3
Jun 15 16:39:01 | loading /lib/multipath/libpriohds.so prioritizer
Jun 15 16:39:01 | sdb: prio = hds (controller setting)
Jun 15 16:39:01 | sdb: prio args = (null) (controller setting)
Jun 15 16:39:01 | sdb: hds prio: VENDOR: HITACHI
Jun 15 16:39:01 | sdb: hds prio: PRODUCT: DF600F
Jun 15 16:39:01 | sdb: hds prio: SERIAL: 0x3000
Jun 15 16:39:01 | sdb: hds prio: LDEV: 0x0000
Jun 15 16:39:01 | sdb: hds prio: CTRL: 1
Jun 15 16:39:01 | sdb: hds prio: PORT: E
Jun 15 16:39:01 | sdb: hds prio: CTRL ODD, LDEV EVEN, PRIO 0 <----------------
PRIO HERE
Jun 15 16:39:01 | sdb: hds prio = 0
Jun 15 16:39:01 | sdb: getuid = /lib/udev/scsi_id --whitelisted
--device=/dev/%n (controller setting)
Jun 15 16:39:01 | sdb: uid = 360060e80104dac0004f349c800000000 (callout)
Jun 15 16:39:01 | Discover device /sys/block/sdc
Jun 15 16:39:01 | sdc: not found in pathvec
Jun 15 16:39:01 | sdc: mask = 0x1f
Jun 15 16:39:01 | sdc: dev_t = 8:32
Jun 15 16:39:01 | sdc: size = 209715200
Jun 15 16:39:01 | sdc: subsystem = scsi
Jun 15 16:39:01 | sdc: vendor = HITACHI
Jun 15 16:39:01 | sdc: product = DF600F
Jun 15 16:39:01 | sdc: rev = 0000
Jun 15 16:39:01 | sdc: h:b:t:l = 8:0:0:0
Jun 15 16:39:01 | sdc: serial = 830530000000
Jun 15 16:39:01 | sdc: get_state
Jun 15 16:39:01 | sdc: path checker = tur (controller setting)
Jun 15 16:39:01 | sdc: state = running
Jun 15 16:39:01 | sdc: state = 3
Jun 15 16:39:01 | sdc: prio = hds (controller setting)
Jun 15 16:39:01 | sdc: prio args = (null) (controller setting)
Jun 15 16:39:01 | sdc: hds prio: VENDOR: HITACHI
Jun 15 16:39:01 | sdc: hds prio: PRODUCT: DF600F
Jun 15 16:39:01 | sdc: hds prio: SERIAL: 0x3000
Jun 15 16:39:01 | sdc: hds prio: LDEV: 0x0000
Jun 15 16:39:01 | sdc: hds prio: CTRL: 2
Jun 15 16:39:01 | sdc: hds prio: PORT: E
Jun 15 16:39:01 | sdc: hds prio: CTRL EVEN, LDEV EVEN, PRIO 1 <---------------
PRIO HERE
Jun 15 16:39:01 | sdc: hds prio = 1
Jun 15 16:39:01 | sdc: getuid = /lib/udev/scsi_id --whitelisted
--device=/dev/%n (controller setting)
Jun 15 16:39:01 | sdc: uid = 360060e80104dac0004f349c800000000 (callout)
In this output, the 2 paths have different priorities and even if we
have set "prio const" in our configuration file, multipathd sets prio
hds on its own.
c) # echo "show config" | multipathd -k
device {
vendor "HITACHI "
product "DF600F.*"
path_grouping_policy multibus
getuid_callout "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
path_checker tur
checker tur
prio const
no_path_retry queue
}
This is the last device entry in the configuration of the running daemon.
d) iostat -m 2
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sda 0.00 0.00 0.00 0 0
dm-0 775.50 96.72 0.00 193 0
dm-1 0.00 0.00 0.00 0 0
dm-2 0.00 0.00 0.00 0 0
dm-3 0.00 0.00 0.00 0 0
sdb 0.00 0.00 0.00 0 0
sdc 775.50 96.72 0.00 193 0 <----- All I/O on one device only.
NOTE: AMS2100 and higher models support active/active architecture and
all paths are considered owner paths and can accept I/O from all
available/assigned ports.
Below are system specifics:
1) lsb_release -rd
Description: Ubuntu 12.04 LTS
Release: 12.04
2) Package version
multipath-tools:
Installed: 0.4.9-3ubuntu5
Candidate: 0.4.9-3ubuntu5
Version table:
*** 0.4.9-3ubuntu5 0
500 http://gr.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
100 /var/lib/dpkg/status
** Affects: multipath-tools (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1013724
Title:
Setting "prio const" in multipath.conf has no effect
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