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multipath on ps5500 with a bit modern Linux - how?

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multipath on ps5500 with a bit modern Linux - how?

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hi everybody,

I'm trying to get multipath do its job but I'm afraid I've got lost as where I make an error/mistake.

There is a few howtos on Dell website but those regards old OS version, one could say ancient, would be great to see those updated, or write anew for oses like rhel 7.x

My problem. I have what I think is simple multipath yet system does not get the Equallogic multipathed.

Could and Eqlx expert cast an eye on the config:

defaults {
  polling_interval       10
  path_selector              "round-robin 0"
  path_grouping_policy   multibus
  prio                           alua
  path_checker              tur
  rr_min_io                    100
  max_fds                      8192
  rr_weight                    priorities
  failback                    immediate
  no_path_retry              fail
  user_friendly_names     yes
}

blacklist {
  devnode ".*"
  wwid    "*"
}
blacklist_exceptions {
    #devnode                 "(sdq|sds|sdr)"
    wwid                    "36090a028004bb5e2faa1e4f9edafc883"
    wwid                    "36090a028004b353affa114faedaf48ca"
    wwid                    "36090a028004bd5c3efa604fbedafc880"
}

multipaths {
  multipath {
    wwid                    36090a028004bb5e2faa1e4f9edafc883
    alias                   equalLogic-0
    path_selector           "round-robin 0"
    path_grouping_policy    group_by_prio
    rr_min_io               10
    rr_weight               priorities
    failback                immediate
    features                "1 queue_if_no_path"
  }
  multipath {
    wwid                    36090a028004b353affa114faedaf48ca
    alias                   equalLogic-1
    path_selector           "round-robin 0"
    path_grouping_policy    group_by_prio
    rr_min_io               10
    rr_weight               priorities
    failback                immediate
    features                "1 queue_if_no_path"
  }
  multipath {
    wwid                    36090a028004bd5c3efa604fbedafc880
    alias                   equalLogic-2
    path_selector           "round-robin 0"
    path_grouping_policy    group_by_prio
    rr_min_io               10
    rr_weight               priorities
    failback                immediate
    features                "1 queue_if_no_path"
  }
}

and suggest what might be wrong there? I don't port-channel client's connection, and the connection is configured like this:

team.config:                            {"runner": {"name": "activebackup", "active": true, "fast_rate": true, "tx_hash": ["eth", "ipv4", "ipv6"]}, "link_watch": {"name": "ethtool"}}

Which I believe should result in iface being what a while ago was called a bond device.

Every help would be great to receive.

L.

All Replies
  • Hello, 

     First with EQL you do NOT want to bond the Ethernet interfaces.  You want to use open-iSCSI to create egress ports so that the initiator will log into the volume for each interface.  Then dev mapper can create the proper MPIO device. 

    Depending on the Distro you can also download HIT/LE which will automate setting up MPIO for Equallogic devices. 

     This Tech Report,  TR1062 has instructions for manually configuring MPIO w/EQL on a RHEL system.  But the same principles apply to any Linux Distro using OPEN-iSCSI initiator.  The location of the files will likely be different. 

     http://en.community.dell.com/cfs-filesystemfile/__key/communityserver-components-postattachments/00-19-86-14-22/TR1062_2D00_LinuxDeploy_2D00_v1-2.pdf

    Regards, 

    Don 

    Social Media and Community Professional
    #IWork4Dell
    Get Support on Twitter - @dellcarespro

  • Hello, 

     Just curious to know if you were able to get MPIO working OK? 

     Regards,

    Don 

    Social Media and Community Professional
    #IWork4Dell
    Get Support on Twitter - @dellcarespro

  • hi, I've seen that doc earlier - that was what I meant by "need ad update, refresh". This one is pretty old and does not cover new, modern versions of popular distros - basically configs are obsolete.

    I have an older sles 10.x which works on a bond iface and works fine, so I thought I could(should) do the same with net team driver.

    My problem I realized was precisely multipath conf. What I learned I think kind of defeat simple logic, but, one never knows, namely:

    blacklist {
      #devnode ".*" << HERE, if in use then even blacklist_exceptions will NOT help
      wwid    "*"
      devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
      devnode "^hd[a-z]"
    }

    and although:

    blacklist_exceptions {
        device {
          vendor  "EQLOGIC"
          product "*"
        }
        wwid                    "36090a028004bb5e2faa1e4f9edafc883"
        wwid                    "36090a028004b353affa114faedaf48ca"
        wwid                    "36090a028004bd5c3efa604fbedafc880"
    }

    multipath would not get the devices.
    So basically blacklist_exceptions seem to have problem, on RHEL / Centos 7.x.

    Or maybe it's just "how this works". So, for now thanks, seems to work, albeit, I'm just starting.

  • Hello, 

     Just to confirm, using teaming/bonding w/EQL storage will not provide same benefits as using Multipathd. 

    There is an updated document for RHEL7   They changed the name so I didn't find it in my earlier search.

    http://en.community.dell.com/techcenter/extras/m/white_papers/20442422

    I don't use "blacklist exceptions.  Those are needed if you what you want to add an exception to something that falls under the exception rule.  Removing that first devnode entry and WWID entry you would only need device info. 

    See if this updated document helps. 

     Regards,

    Don 

    Social Media and Community Professional
    #IWork4Dell
    Get Support on Twitter - @dellcarespro