Re: [ovirt-users] Adding FCP - Request for comments

From: "Daniel Helgenberger" <daniel.helgenberger(a)m-box.de&gt; To: "Nir Soffer" <nsoffer(a)redhat.com&gt; Cc: "Fábio Coelho" <fabio.coelho(a)jfsc.jus.br&gt;, "users" <Users(a)ovirt.org&gt; Sent: Friday, May 22, 2015 11:13:31 PM Subject: Re: [ovirt-users] Adding FCP - Request for comments On 22.05.2015 21:08, Nir Soffer wrote: > ----- Original Message ----- >> From: "Daniel Helgenberger" <daniel.helgenberger(a)m-box.de&gt; >> To: "Fábio Coelho" <fabio.coelho(a)jfsc.jus.br&gt;, "users" <Users(a)ovirt.org&gt; >> Sent: Wednesday, May 20, 2015 8:46:01 PM >> Subject: Re: [ovirt-users] Adding FCP - Request for comments >> >> >> >> On 20.05.2015 19:10, Fábio Coelho wrote: >> Hello Fabio, >>> Thoughts about Adding Storage Luns >>> >>> As I am new here, I would appreciate some advice about some actions that >>> I >>> intend to perform, please read. >>> >>> I have added a LUN to my cluster and, for that task, I had to restart >>> every >>> node >>> of it. There was no LUNs before, multipathd was stopped and >>> multipath.conf >>> inexisted. I was able to log in and manually configure multipath.conf, a >>> simple >>> multipathd start was not enough. >> In theory this should have been enough. What puzzles me: Until now >> host-deploy always activated multipathd and writes a multipath.conf. >> >> Here I strongly recommend to blacklist everything and then only white >> listing your vendors. Otherwise your error logs fill up and you cannot >> connect any USB stick to the host any more ;) >> >> Then, add RHEV PRIVATE to the second line otherwise it will be >> overwritten on every host deploy run. >> # RHEV PRIVATE >> >> blacklist { >> device { >> vendor "*" >> product "*" >> } >> } > > This is bad idea. If you want to blacklist all devices, you can add this to > vdsm generated configuration. What can I add? > > Vdsm is depending on the defaults set in the "defaults" section. I just looked; seems to me this is the default part vdsm is needing? 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 }

The problem is there is no blacklisting at all in the default multipath.conf - at least not in mine. I know this is a hard thing to do for a general version of the file witch works for anyone. As for my part I have only very specific devices / vendors I want to have in my multipah.conf; so I blacklist everything and later on add blacklist exceptions like: blacklist_exceptions { device { vendor "IFT" product "*" } } Witch IMHO is (was?) since best practice a long time ago when I created my configs.

> >> >> >> >> After activating multipathd and editing multipath.conf to your needs you >> would actually need to run the 'multipath' command to create the paths. >> [1] >> >> Sometimes you need to rescan the LUNs, though, esp. if you changed sizes >> after activating them. >>> >>> If this wasn't enough, my double NetAPP ( through an Hitachi ) provided >>> me >>> with >>> a not so empty brand new LUN, and the task to add the FCP failed to point >>> this. >>> Trusting my double, I spent some precious time searching for different >>> problems, >>> until receiving some guidance and do a simple dd if=/dev/zero to the >>> initial >>> blocks of the LUN. >> IMHO you need to initialize the lun with a partition table at least >> (parted). dd will do also. >> >>> >>> Consulting the documentation >>> ( http://www.ovirt.org/OVirt_Administration_Guide#Adding_FCP_Storage ) >>> for >>> this >>> matters, was not of any help. >>> >>> So, my questions: >>> >>> This is the intended behavior? Should I open a ticket? >>> >>> Should I add a note to documentation to point such behavior? ( i'm about >>> to >>> ) >>> >> I think this is not ovirts part but rather dm-multipath. My best guess >> would be a configuration error on your part? >> >> [1] >> https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/... >>> >>> Cheers, >>> >>> by qoelheX >>> >>> >>> Aviso Legal >>> >>> A informação contida neste e-mail e em seus anexos pode ser restrita, >>> sendo >>> o >>> emitente deste responsável por seu conteúdo e endereçamento. Se você não >>> for a >>> pessoa autorizada a receber esta mensagem e tendo recebido a mesma por >>> engano, >>> favor apagá-la imediatamente. A JFSC considera opiniões, conclusões e >>> outras >>> informações não oficiais de responsabilidade do usuário deste serviço. >>> >> >> -- >> Daniel Helgenberger >> m box bewegtbild GmbH >> >> P: +49/30/2408781-22 >> F: +49/30/2408781-10 >> >> ACKERSTR. 19 >> D-10115 BERLIN >> >> >> www.m-box.de www.monkeymen.tv >> >> Geschäftsführer: Martin Retschitzegger / Michaela Göllner >> Handeslregister: Amtsgericht Charlottenburg / HRB 112767 >> _______________________________________________ >> Users mailing list >> Users(a)ovirt.org >> http://lists.ovirt.org/mailman/listinfo/users >> > -- Daniel Helgenberger m box bewegtbild GmbH P: +49/30/2408781-22 F: +49/30/2408781-10 ACKERSTR. 19 D-10115 BERLIN www.m-box.de www.monkeymen.tv Geschäftsführer: Martin Retschitzegger / Michaela Göllner Handeslregister: Amtsgericht Charlottenburg / HRB 112767