----- Original Message -----
From: "Daniel Helgenberger" <daniel.helgenberger@m-box.de> To: "Nir Soffer" <nsoffer@redhat.com> Cc: "Fábio Coelho" <fabio.coelho@jfsc.jus.br>, "users" <Users@ovirt.org> 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@m-box.de> To: "Fábio Coelho" <fabio.coelho@jfsc.jus.br>, "users" <Users@ovirt.org> 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 }
Right, if you have these you should be fine.
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.
We try to make it work for everyone without extra configuration, so we cannot use automatic blacklisting. My comments was only about multpath.conf without "defaults" section. Thanks, Nir
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/htm...
Cheers,
by qoelheX
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-- 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