Multipath and Xenserver?

[To-M]

Link for the Virtual Iron setup.

http://www.open-e.com/library/product-presentations/

Library
Product Presentations

Open-E in Virtual Appliances

2009 - Multipath with Virtual Iron and Open-E Data Storage Server, December 2008

You are correct that when setting up a LUN it is for the Target that you wish to assign for only.

[red]

im fooling a bit with xenserver, it seems like open-e really dosnt report multiple paths to the target, but there is a little manual workaround

first my device in multipath.conf:


device {
vendor "iSCSI"
product "*"
path_grouping_policy multibus
path_checker tur
features "1 queue_if_no_path"
failback immediate
rr_min_io 1000 # try different values, for me 4 seems to work best
path_selector "round-robin 0"
}

since xen allows only to setup one connection to a specific lun, you have to setup another connection manually, for example:
- iscsi target (open-e) on 192.168.0.1/24 and 192.168.1.1/24
- in xencenter activate multipath
- setup SR to 192.168.0.1
- login to xen via ssh
- iscsi login to the 192.168.1.1:
"iscsiadm --mode discovery --type sendtargets --portal 192.168.1.1
iscsiadm --mode node --targetname iqn.2009-04:dss.target0 --portal 192.168.1.1 --login"

at this moment xencenter should report 2 active paths to the SR.. well there should be a way to make it automatic but didnt see in to it yet, also i would suggest to read dm-multipath manual

[icepicknz]

I tired, but xenserver still says only 1 of 1 multipaths:

Login session [iface: default, target: iqn.2010-05:iscsi.target0, portal: 172.16.32.200,3260]
Login session [iface: default, target: iqn.2010-05:iscsi.target0, portal: 172.16.31.200,3260]
[root@Unix02 ~]# multipath -ll
200000000d11ba481dm-3 SCST_FIO,0a1Fm75r3fC3oD
[size=5.4T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 12:0:0:0 sdc 8:32 [active][ready]
SATA_ST31000340NS_9QJ39EV2dm-0 ATA,ST31000340NS
[size=932G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 1:0:0:0 sdb 8:16 [active][ready]
[root@Unix02 ~]#


[root@Unix02 ~]# /etc/init.d/multipathd restart
Stopping multipathd daemon: [ OK ]
Starting multipathd daemon: [ OK ]
[root@Unix02 ~]# multipath -ll
200000000d11ba481dm-3 SCST_FIO,0a1Fm75r3fC3oD
[size=5.4T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=2][enabled]
\_ 12:0:0:0 sdc 8:32 [active][ready]
\_ 13:0:0:0 sdd 8:48 [active][ready]
SATA_ST31000340NS_9QJ39EV2dm-0 ATA,ST31000340NS
[size=932G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 1:0:0:0 sdb 8:16 [active][ready]
[root@Unix02 ~]#




I added the following config:
# BARRY ADDED
device {
vendor "iSCSI"
product "*"
path_grouping_policy multibus
path_checker tur
features "1 queue_if_no_path"
failback immediate
rr_min_io 4 # try different values, for me 4 seems to work best
path_selector "round-robin 0"
}

device {
vendor "SCST_FIO"
product "*"
path_grouping_policy multibus
path_checker tur
features "1 queue_if_no_path"
failback immediate
rr_min_io 4 # try different values, for me 4 seems to work best
path_selector "round-robin 0"
}


And also:
multipaths {
multipath {
wwid 200000000d11ba481dm-2
alias multipath2
}

Any help would be appreciated.

thanks
Barry

[icepicknz]

In addition here is a verbose output:

sdc: not found in pathvec
sdc: mask = 0x5
sdc: bus = 1
sdc: dev_t = 8:32
sdc: size = 11702837248
sdc: vendor = SCST_FIO
sdc: product = 0a1Fm75r3fC3oDLw
sdc: rev = 101
sdc: h:b:t:l = 12:0:0:0
sdc: path checker = tur (controller setting)
sdc: state = 2
sdd: not found in pathvec
sdd: mask = 0x5
sdd: bus = 1
sdd: dev_t = 8:48
sdd: size = 11702837248
sdd: vendor = SCST_FIO
sdd: product = 0a1Fm75r3fC3oDLw
sdd: rev = 101
sdd: h:b:t:l = 13:0:0:0
sdd: path checker = tur (controller setting)
sdd: state = 2
===== paths list =====
uuid hcil dev dev_t pri dm_st chk_st vend/prod/rev
0:0:0:0 sda 8:0 0 [undef][ready] ATA,ST3500641AS
1:0:0:0 sdb 8:16 0 [undef][ready] ATA,ST31000340NS
12:0:0:0 sdc 8:32 0 [undef][ready] SCST_FIO,0a1Fm75r3fC3oDLw
13:0:0:0 sdd 8:48 0 [undef][ready] SCST_FIO,0a1Fm75r3fC3oDLw
params = 1 queue_if_no_path 0 1 1 round-robin 0 2 1 8:32 4 8:48 4
status = 2 0 0 0 1 1 A 0 2 0 8:32 A 0 8:48 A 0
sdc: mask = 0x8
sdc: getprio = NULL (internal default)
sdc: prio = 1
sdd: mask = 0x8
sdd: getprio = NULL (internal default)
sdd: prio = 1
200000000d11ba481dm-3 SCST_FIO,0a1Fm75r3fC3oD
[size=5.4T][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=2][active]
\_ 12:0:0:0 sdc 8:32 [active][ready]
\_ 13:0:0:0 sdd 8:48 [active][ready]
params = 0 0 1 1 round-robin 0 1 1 8:16 5
status = 2 0 0 0 1 1 A 0 1 0 8:16 A 0
sdb: mask = 0x8
sdb: getprio = NULL (internal default)
sdb: prio = 1
SATA_ST31000340NS_9QJ39EV2dm-0 ATA,ST31000340NS
[size=932G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 1:0:0:0 sdb 8:16 [active][ready]