[ovirt-users] iscsi config for dell ps series

[Gianluca Cecchi]

Hello,
I'm configuring an hypervisor for iSCSI Dell PS Series
It is a CentOS 7.3 + updates server.
The server has been already added to oVirt as a node, but without any
storage domain configured yet.
It has access to one lun that will become the storage domain one.

Default oVirt generated multipath.conf is like this:

defaults {
    polling_interval            5
    no_path_retry               fail
    user_friendly_names         no
    flush_on_last_del           yes
    fast_io_fail_tmo            5
    dev_loss_tmo                30
    max_fds                     4096
}

devices {
    device {
        # These settings overrides built-in devices settings. It does not
apply
        # to devices without built-in settings (these use the settings in
the
        # "defaults" section), or to devices defined in the "devices"
section.
        # Note: This is not available yet on Fedora 21. For more info see
        # https://bugzilla.redhat.com/1253799
        all_devs                yes
        no_path_retry           fail
    }
}


Apparently in device-mapper-multipath there is no builtin for this
combination

  Vendor: EQLOGIC  Model: 100E-00          Rev: 8.1

So, with the oVirt provided configuration a "show config" for multipath
reports something like this at the end:

        polling_interval 5
        path_selector "service-time 0"
        path_grouping_policy "failover"
        path_checker "directio"
        rr_min_io_rq 1
        max_fds 4096
        rr_weight "uniform"
        failback "manual"
        features "0"

and multipath layout this way

[root at ov300 etc]# multipath -l
364817197b5dfd0e5538d959702249b1c dm-3 EQLOGIC ,100E-00
size=1.0T features='0' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| `- 7:0:0:0 sde 8:64 active undef  running
`-+- policy='service-time 0' prio=0 status=enabled
  `- 8:0:0:0 sdf 8:80 active undef  running
[root at ov300 etc]#

Following recommendations from Dell here:
http://en.community.dell.com/techcenter/extras/m/white_papers/20442422

I should put into defaults section these directives:

defaults {
    polling_interval            10
    path_selector               "round-robin 0"
    path_grouping_policy        multibus
    path_checker                tur
    rr_min_io_rq                10
    max_fds                     8192
    rr_weight                   priorities
    failback                    immediate
    features                    0
}

I'm trying to mix EQL and oVirt reccomendations to have the best for my use
and arrived at this config (plus a blacklist section with my internal hd
and my flash wwids that is not relevant here):

# VDSM REVISION 1.3
# VDSM PRIVATE

defaults {
    polling_interval            5
    no_path_retry               fail
    user_friendly_names         no
    flush_on_last_del           yes
    fast_io_fail_tmo            5
    dev_loss_tmo                30
#    Default oVirt value overwritten
#    max_fds                     4096
#
    max_fds                     8192
}

devices {
    device {
        # These settings overrides built-in devices settings. It does not
apply
        # to devices without built-in settings (these use the settings in
the
        # "defaults" section), or to devices defined in the "devices"
section.
        # Note: This is not available yet on Fedora 21. For more info see
        # https://bugzilla.redhat.com/1253799
        all_devs                yes
        no_path_retry           fail
    }
    device {
        vendor                  "EQLOGIC"
        product                 "100E-00"
#        Default EQL configuration overwritten by oVirt default
#        polling_interval        10
#
        path_selector           "round-robin 0"
        path_grouping_policy    multibus
        path_checker            tur
        rr_min_io_rq            10
        rr_weight               priorities
        failback                immediate
        features                "0"
    }
}

After activating this config I have this mutipath layout

[root at ov300 etc]# multipath -l
364817197b5dfd0e5538d959702249b1c dm-3 EQLOGIC ,100E-00
size=1.0T features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=0 status=active
  |- 7:0:0:0 sde 8:64 active undef  running
  `- 8:0:0:0 sdf 8:80 active undef  running
[root at ov300 etc]#

NOTE: at this moment the storage is not yet configured as a storage domain.
I also changed /etc/iscsi/iscsd.conf and sysctl.d parameters as from EQL
doc indications

>From an iSCSI initiator point of view:

[root at ov300 ~]# iscsiadm -m session
tcp: [1] 10.10.100.9:3260,1
iqn.2001-05.com.equallogic:4-771816-e5d0dfb59-1c9b240297958d53-ovsd3910
(non-flash)
tcp: [2] 10.10.100.9:3260,1
iqn.2001-05.com.equallogic:4-771816-e5d0dfb59-1c9b240297958d53-ovsd3910
(non-flash)
[root at ov300 ~]#

[root at ov300 ~]# iscsiadm -m session -P 1
Target:
iqn.2001-05.com.equallogic:4-771816-e5d0dfb59-1c9b240297958d53-ovsd3910
(non-flash)
Current Portal: 10.10.100.41:3260,1
Persistent Portal: 10.10.100.9:3260,1
**********
Interface:
**********
Iface Name: ip1p1
Iface Transport: tcp
Iface Initiatorname: iqn.1994-05.com.redhat:f2d7fc1e2fc
Iface IPaddress: 10.10.100.87
Iface HWaddress: <empty>
Iface Netdev: <empty>
SID: 1
iSCSI Connection State: LOGGED IN
iSCSI Session State: LOGGED_IN
Internal iscsid Session State: NO CHANGE
Current Portal: 10.10.100.42:3260,1
Persistent Portal: 10.10.100.9:3260,1
**********
Interface:
**********
Iface Name: ip1p2
Iface Transport: tcp
Iface Initiatorname: iqn.1994-05.com.redhat:f2d7fc1e2fc
Iface IPaddress: 10.10.100.87
Iface HWaddress: <empty>
Iface Netdev: <empty>
SID: 2
iSCSI Connection State: LOGGED IN
iSCSI Session State: LOGGED_IN
Internal iscsid Session State: NO CHANGE
[root at ov300 ~]#

Do you think it is ok?

Thanks for any comments,

Gianluca
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