how to configure ISCSI fault tolerance in ubuntu 12.04

Question

how to configure ISCSI fault tolerance in ubuntu 12.04 Anyone has a tutorial or steps to?! thanks in advance knowing that initiator and server are ubuntu

Answer 1

I had Ubuntu 10.10 working with my Equallogic PS6000 very well. I upgraded to Ubuntu 12.04 and it stopped working. I am not new to open-iscsi/multipath tools - but it is being a real bugger. Anyway, maybe some of this will help, the vagaries of chap are not included and I promise that it is likely incomplete but this should point you in the right direction:

Install open-iscsi
Set up your interfaces:

$iscsiadm --mode iface --op=new --interface iscsi-1
$iscsiadm --mode iface --op=new --interface iscsi-2

$iscsiadm --mode iface --op=update --interface iscsi-1 --name=iface.net_ifacename --value=eth1 

$iscsiadm --mode iface --op=update --interface iscsi-2 --name=iface.net_ifacename --value=eth2

Discover luns:

$iscsiadm -m discovery -t sendtargets -p 10.0.1.10

You should see a list of permitted luns, they should look something like:

10.0.1.10:3260,1 iqn.2001-05.com.equallogic:xxxxxxxx
10.0.1.10:3260,1 iqn.2001-05.com.equallogic:xxxxxxxx

log in to the luns:

$iscsiadm --mode node --targetname iqn.2001-05.com.equallogic:xxxxxxxx --portal 10.0.1.10:3260 --login all

Verify you are connected:

$iscsiadm -m session
tcp: [1] 10.0.1.10:3260,1 iqn.2001-05.com.equallogic:xxxxxxxx
tcp: [2] 10.0.1.10:3260,1 iqn.2001-05.com.equallogic:xxxxxxxx

Tell it to log in automatically at startup:

$iscsiadm --mode node --targetname iqn.2001-05.com.equallogic:xxxxxxxx --portal 10.0.1.10:3260 --op update -n node.startup -v automatic

Install multipath-tools

Create /etc/multipath.conf - here is a sample:

##################################
defaults {
    user_friendly_names yes
    find_multipaths yes
}
#ignore local drives
blacklist {
    devnode "^sd[a,b]$"
}
#Pay attention to these devices
blacklist_exceptions {
    devnode "^dm-0"
    devnode "^dm-1"
    devnode "^dm-2"
    devnode "^sd[c,d,e,f]"
}
#device description for a PS6000
devices {
    device {
      vendor                  "EQLOGIC"
      product                 "100E-00"
      path_grouping_policy    multibus
      getuid_callout          "/lib/udev/scsi_id --whitelisted --device=/dev/%n"
      features                "0 queue_if_no_path"
      path_checker            readsector0
      path_selector           "round-robin 0"
      failback                immediate
      rr_min_io               10
      rr_weight               priorities
    }
}
#############################

Restart multipath tools -

Check topology/map:

multipath -ll

(here is where Ubuntu 12.04 broke - I stopped seeing anything)

expected result:

    myLun (UUIDxxxxxx) dm-1 EQLOGIC,100E-00
        size=100G features='1 queue_if_no_path' hwhandler='0' wp=rw
        `-+- policy='round-robin 0' prio=2 status=active
        |- 4:0:0:0 sde 8:64 active ready running
        `- 3:0:0:0 sdc 8:32 active ready running

I hope this helps. Now off to fix mine... :-)