[dm-devel] Problem using dm-multipath on first of 2 LUNs on system
Gerald Nowitzky
Nowitzky at igne.de
Tue Jan 29 16:58:48 UTC 2008
try and remove dm-0 to dm-4 from the blacklist. The devices in /dev/mapper are links to /dev/dm-x
(Gerald)
----- Original Message -----
From: LittleJ at AE.com
To: dm-devel at redhat.com
Sent: Tuesday, January 29, 2008 4:42 PM
Subject: [dm-devel] Problem using dm-multipath on first of 2 LUNs on system
I am attempting to implement dm-multipath on a RHEL4U6 server and I have been successful in enabling it on the second of 2 LUNs on the server but for whatever reason it will not create the device special files in /dev/mapper for the fist LUN. `multipath -d` shows that it identifies the first LUN and wants to create the mpath0 files:
[root at svwdcvispay01 etc]# multipath -d
create: mpath0 (36005076801810085c800000000000194)
[size=12 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [prio=50]
\_ 1:0:0:0 sda 8:0 [ready]
\_ round-robin 0 [prio=10]
\_ 1:0:1:0 sdc 8:32 [ready]
switchpg: mpath1 (36005076801810085c8000000000001a2)
[size=50 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [prio=50]
\_ 1:0:1:1 sdd 8:48 [active][ready]
\_ round-robin 0 [prio=10]
\_ 1:0:0:1 sdb 8:16 [active][ready]
[root at svwdcvispay01 etc]#
However `multipath -v3` generates a "set ACT_CREATE: map does not exists" error in the mpath0 section:
[root at svwdcvispay01 etc]# multipath -v3
load path identifiers cache
#
# all paths in cache :
#
36005076801810085c800000000000194 1:0:0:0 sda 8:0 IBM /2145
36005076801810085c8000000000001a2 1:0:0:1 sdb 8:16 10 [active] IBM /2145
36005076801810085c800000000000194 1:0:1:0 sdc 8:32 IBM /2145
36005076801810085c8000000000001a2 1:0:1:1 sdd 8:48 50 [active] IBM /2145
dm-0 blacklisted
dm-1 blacklisted
dm-2 blacklisted
dm-3 blacklisted
dm-4 blacklisted
md0 blacklisted
ram0 blacklisted
ram10 blacklisted
ram11 blacklisted
ram12 blacklisted
ram13 blacklisted
ram14 blacklisted
ram15 blacklisted
ram1 blacklisted
ram2 blacklisted
ram3 blacklisted
ram4 blacklisted
ram5 blacklisted
ram6 blacklisted
ram7 blacklisted
ram8 blacklisted
ram9 blacklisted
===== path info sda (mask 0x1f) =====
bus = 1
dev_t = 8:0
size = 25165824
vendor = IBM
product = 2145
rev = 0000
h:b:t:l = 1:0:0:0
tgt_node_name = 0x50050768010010b9
serial = 020060402172XX00
path checker = tur (controler setting)
state = 2
getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
prio = 50
uid = 36005076801810085c800000000000194 (cache)
===== path info sdb (mask 0x1f) =====
bus = 1
dev_t = 8:16
size = 104857600
vendor = IBM
product = 2145
rev = 0000
h:b:t:l = 1:0:0:1
tgt_node_name = 0x50050768010010b9
serial = 020060402172XX00
path checker = tur (controler setting)
state = 2
getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
prio = 10
uid = 36005076801810085c8000000000001a2 (cache)
===== path info sdc (mask 0x1f) =====
bus = 1
dev_t = 8:32
size = 25165824
vendor = IBM
product = 2145
rev = 0000
h:b:t:l = 1:0:1:0
tgt_node_name = 0x5005076801001082
serial = 020060402172XX00
path checker = tur (controler setting)
state = 2
getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
prio = 10
uid = 36005076801810085c800000000000194 (cache)
===== path info sdd (mask 0x1f) =====
bus = 1
dev_t = 8:48
size = 104857600
vendor = IBM
product = 2145
rev = 0000
h:b:t:l = 1:0:1:1
tgt_node_name = 0x5005076801001082
serial = 020060402172XX00
path checker = tur (controler setting)
state = 2
getprio = /sbin/mpath_prio_alua /dev/%n (controler setting)
prio = 50
uid = 36005076801810085c8000000000001a2 (cache)
#
# all paths :
#
36005076801810085c800000000000194 1:0:0:0 sda 8:0 50 [ready] IBM /2145
36005076801810085c8000000000001a2 1:0:0:1 sdb 8:16 10 [active][ready] IBM
36005076801810085c800000000000194 1:0:1:0 sdc 8:32 10 [ready] IBM /2145
36005076801810085c8000000000001a2 1:0:1:1 sdd 8:48 50 [active][ready] IBM
params = 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000 round-robin 0 1 1 8:16 1000
status = 1 0 0 2 1 A 0 1 0 8:48 A 0 E 0 1 0 8:16 A 0
Found matching wwid [36005076801810085c800000000000194] in bindings file.
Setting alias to mpath0
pgpolicy = group_by_prio (controler setting)
selector = round-robin 0 (internal default)
features = 1 queue_if_no_path (controler setting)
hwhandler = 0 (controler setting)
rr_weight = 1 (internal default)
rr_min_io = 1000 (config file default)
no_path_retry = NONE (internal default)
pg_timeout = NONE (internal default)
0 25165824 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:0 1000 round-robin 0 1 1 8:32 1000
set ACT_CREATE: map does not exists
Found matching wwid [36005076801810085c8000000000001a2] in bindings file.
Setting alias to mpath1
pgpolicy = group_by_prio (controler setting)
selector = round-robin 0 (internal default)
features = 1 queue_if_no_path (controler setting)
hwhandler = 0 (controler setting)
rr_weight = 1 (internal default)
rr_min_io = 1000 (config file default)
no_path_retry = NONE (internal default)
pg_timeout = NONE (internal default)
0 104857600 multipath 1 queue_if_no_path 0 2 1 round-robin 0 1 1 8:48 1000 round-robin 0 1 1 8:16 1000
set ACT_NOTHING: map unchanged
[root at svwdcvispay01 etc]#
And notice that no /dev/mapper/mpath0 device special files were created:
[root at svwdcvispay01 etc]# ls -la /dev/mapper
total 0
drwxr-xr-x 2 root root 160 Jan 29 09:53 .
drwxr-xr-x 9 root root 4900 Jan 29 09:51 ..
crw------- 1 root root 10, 63 Jan 21 16:15 control
brw-rw---- 1 root disk 253, 0 Jan 21 16:15 mpath1
brw-rw---- 1 root disk 253, 1 Jan 21 16:15 mpath1p1
brw-rw---- 1 root disk 253, 2 Jan 21 16:15 mpath1p2
brw-rw---- 1 root disk 253, 3 Jan 21 16:15 mpath1p3
brw-rw---- 1 root disk 253, 4 Jan 21 16:15 mpath1p5
[root at svwdcvispay01 etc]#
My /etc/multipath.conf file is basic but I have tried creating an alias entry that looks like "multipaths {multipath {wwid 36005076801810085c800000000000194 alias os}}" for the first LUN but the results are the same, it still won't create any device special files for the first LUN.
[root at svwdcvispay01 mapper]# cat /etc/multipath.conf | grep -v "#"
defaults {
user_friendly_names yes
}
[root at svwdcvispay01 mapper]#
I have been working this issue for over a week with IBM and RedHat tech support and they have been unhelpful. I need to get this functional because the server in question has been unstable using a single path to the SAN due to stability issues we have had periodically with one of the SAN Volume Controllers. If additional information is needed to troubleshoot this please let me know.
Joe little
littlej at ae.com
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