[ovirt-users] storage redundancy in Ovirt

FERNANDO FREDIANI fernando.frediani at upx.com
Mon Apr 17 14:31:34 UTC 2017


Thanks for the clarification Adam.

That makes total sense.

Reagrds
Fernando

On 17/04/2017 11:28, Adam Litke wrote:
>
>
> On Mon, Apr 17, 2017 at 9:12 AM, FERNANDO FREDIANI 
> <fernando.frediani at upx.com <mailto:fernando.frediani at upx.com>> wrote:
>
>     Should I understand then that fecing is not mandatory, just
>     advised and there are no downtimes to the rest of the cluster if a
>     pending manual action has to be done to confirm a host has been
>     rebooted in order to move the SPM to another live host. Perhaps
>     only effect is not be able to add new hosts and connect to storage
>     or something ?
>
> A missing SPM will not affect existing VMs.  Running VMs (on hosts 
> other than the SPM host) will continue to run normally and you can 
> even start existing VMs.  Without an SPM you will not be able to 
> manipulate the storage (Add/remove domains, add/remove disks, migrate 
> disks, etc).
>
>     Fernando
>
>     On 17/04/2017 10:06, Nir Soffer wrote:
>>     On Mon, Apr 17, 2017 at 8:24 AM Konstantin Raskoshnyi
>>     <konrasko at gmail.com <mailto:konrasko at gmail.com>> wrote:
>>
>>         But actually, it didn't work well. After main SPM host went
>>         down I see this
>>         Screen Shot 2017-04-16 at 10.22.00 PM.png
>>
>>         2017-04-17 05:23:15,554Z ERROR
>>         [org.ovirt.engine.core.vdsbroker.irsbroker.IrsProxy]
>>         (DefaultQuartzScheduler5)
>>         [4dcc033d-26bf-49bb-bfaa-03a970dbbec1] SPM Init: could not
>>         find reported vds or not up - pool: 'STG' vds_spm_id: '1'
>>         2017-04-17 05:23:15,567Z INFO
>>          [org.ovirt.engine.core.vdsbroker.irsbroker.IrsProxy]
>>         (DefaultQuartzScheduler5)
>>         [4dcc033d-26bf-49bb-bfaa-03a970dbbec1] SPM selection - vds
>>         seems as spm 'tank5'
>>         2017-04-17 05:23:15,567Z WARN
>>          [org.ovirt.engine.core.vdsbroker.irsbroker.IrsProxy]
>>         (DefaultQuartzScheduler5)
>>         [4dcc033d-26bf-49bb-bfaa-03a970dbbec1] spm vds is non
>>         responsive, stopping spm selection.
>>
>>         So that means only if BMC is up it's possible to
>>         automatically switch  SPM host?
>>
>>
>>     BMC?
>>
>>     If your SPM is no responsive, the system will try to fence it.
>>     Did you
>>     configure power management for all hosts? did you check that it
>>     work? How did you simulate non-responsive host?
>>
>>     If power management is not configured or fail, the system cannot
>>     move the spm to another host, unless you manually confirm that the
>>     SPM host was rebooted.
>>
>>     Nir
>>
>>
>>         Thanks
>>
>>         On Sun, Apr 16, 2017 at 8:29 PM, Konstantin Raskoshnyi
>>         <konrasko at gmail.com <mailto:konrasko at gmail.com>> wrote:
>>
>>             Oh, fence agent works fine if I select ilo4,
>>             Thank you for your help!
>>
>>             On Sun, Apr 16, 2017 at 8:22 PM Dan Yasny
>>             <dyasny at gmail.com <mailto:dyasny at gmail.com>> wrote:
>>
>>                 On Sun, Apr 16, 2017 at 11:19 PM, Konstantin
>>                 Raskoshnyi <konrasko at gmail.com
>>                 <mailto:konrasko at gmail.com>> wrote:
>>
>>                     Makes sense.
>>                     I was trying to set it up, but doesn't work with
>>                     our staging hardware.
>>                     We have old ilo100, I'll try again.
>>                     Thanks!
>>
>>
>>                 It is absolutely necessary for any HA to work
>>                 properly. There's of course the "confirm host has
>>                 been shutdown" option, which serves as an override
>>                 for the fence command, but it's manual
>>
>>                     On Sun, Apr 16, 2017 at 8:18 PM Dan Yasny
>>                     <dyasny at gmail.com <mailto:dyasny at gmail.com>> wrote:
>>
>>                         On Sun, Apr 16, 2017 at 11:15 PM, Konstantin
>>                         Raskoshnyi <konrasko at gmail.com
>>                         <mailto:konrasko at gmail.com>> wrote:
>>
>>                             Fence agent under each node?
>>
>>
>>                         When you configure a host, there's the power
>>                         management tab, where you need to enter the
>>                         bmc details for the host. If you don't have
>>                         fencing enabled, how do you expect the system
>>                         to make sure a host running a service is
>>                         actually down (and it is safe to start HA
>>                         services elsewhere), and not, for example,
>>                         just unreachable by the engine? How do you
>>                         avoid a splitbraid -> SBA ?
>>
>>
>>                             On Sun, Apr 16, 2017 at 8:14 PM Dan Yasny
>>                             <dyasny at gmail.com
>>                             <mailto:dyasny at gmail.com>> wrote:
>>
>>                                 On Sun, Apr 16, 2017 at 11:13 PM,
>>                                 Konstantin Raskoshnyi
>>                                 <konrasko at gmail.com
>>                                 <mailto:konrasko at gmail.com>> wrote:
>>
>>                                     "Corner cases"?
>>                                     I tried to simulate crash of SPM
>>                                     server and ovirt kept trying to
>>                                     reistablished connection to the
>>                                     failed node.
>>
>>
>>                                 Did you configure fencing?
>>
>>
>>
>>                                     On Sun, Apr 16, 2017 at 8:10 PM
>>                                     Dan Yasny <dyasny at gmail.com
>>                                     <mailto:dyasny at gmail.com>> wrote:
>>
>>                                         On Sun, Apr 16, 2017 at 7:29
>>                                         AM, Nir Soffer
>>                                         <nsoffer at redhat.com
>>                                         <mailto:nsoffer at redhat.com>>
>>                                         wrote:
>>
>>                                             On Sun, Apr 16, 2017 at
>>                                             2:05 PM Dan Yasny
>>                                             <dyasny at redhat.com
>>                                             <mailto:dyasny at redhat.com>>
>>                                             wrote:
>>
>>
>>
>>                                                 On Apr 16, 2017 7:01
>>                                                 AM, "Nir Soffer"
>>                                                 <nsoffer at redhat.com
>>                                                 <mailto:nsoffer at redhat.com>>
>>                                                 wrote:
>>
>>                                                     On Sun, Apr 16,
>>                                                     2017 at 4:17 AM
>>                                                     Dan Yasny
>>                                                     <dyasny at gmail.com
>>                                                     <mailto:dyasny at gmail.com>>
>>                                                     wrote:
>>
>>                                                         When you set
>>                                                         up a storage
>>                                                         domain, you
>>                                                         need to
>>                                                         specify a
>>                                                         host to
>>                                                         perform the
>>                                                         initial
>>                                                         storage
>>                                                         operations,
>>                                                         but once the
>>                                                         SD is
>>                                                         defined, it's
>>                                                         details are
>>                                                         in the engine
>>                                                         database, and
>>                                                         all the hosts
>>                                                         get connected
>>                                                         to it
>>                                                         directly. If
>>                                                         the first
>>                                                         host you used
>>                                                         to define the
>>                                                         SD goes down,
>>                                                         all other
>>                                                         hosts will
>>                                                         still remain
>>                                                         connected and
>>                                                         work. SPM is
>>                                                         an HA
>>                                                         service, and
>>                                                         if the
>>                                                         current SPM
>>                                                         host goes
>>                                                         down, SPM
>>                                                         gets started
>>                                                         on another
>>                                                         host in the
>>                                                         DC. In short,
>>                                                         unless your
>>                                                         actual NFS
>>                                                         exporting
>>                                                         host goes
>>                                                         down, there
>>                                                         is no outage.
>>
>>
>>                                                     There is no
>>                                                     storage outage,
>>                                                     but if you
>>                                                     shutdown the spm
>>                                                     host, the spm host
>>                                                     will not move to
>>                                                     a new host until
>>                                                     the spm host is
>>                                                     online again, or
>>                                                     you confirm
>>                                                     manually that the
>>                                                     spm host was
>>                                                     rebooted.
>>
>>
>>                                                 In a properly
>>                                                 configured setup the
>>                                                 SBA should take care
>>                                                 of that. That's the
>>                                                 whole point of HA
>>                                                 services
>>
>>
>>                                             In some cases like power
>>                                             loss or hardware failure,
>>                                             there is no way to start
>>                                             the spm host, and the
>>                                             system cannot recover
>>                                             automatically.
>>
>>
>>                                         There are always corner
>>                                         cases, no doubt. But in a
>>                                         normal situation. where an
>>                                         SPM host goes down because of
>>                                         a hardware failure, it gets
>>                                         fenced, other hosts contend
>>                                         for SPM and start it. No
>>                                         surprises there.
>>
>>
>>                                             Nir
>>
>>
>>
>>                                                     Nir
>>
>>
>>                                                         On Sat, Apr
>>                                                         15, 2017 at
>>                                                         1:53 PM,
>>                                                         Konstantin
>>                                                         Raskoshnyi
>>                                                         <konrasko at gmail.com
>>                                                         <mailto:konrasko at gmail.com>>
>>                                                         wrote:
>>
>>                                                             Hi Fernando,
>>                                                             I see
>>                                                             each host
>>                                                             has
>>                                                             direct
>>                                                             connection
>>                                                             nfs
>>                                                             mount,
>>                                                             but yes,
>>                                                             if main
>>                                                             host to
>>                                                             which I
>>                                                             connected
>>                                                             nfs
>>                                                             storage
>>                                                             going
>>                                                             down the
>>                                                             storage
>>                                                             becomes
>>                                                             unavailable
>>                                                             and all
>>                                                             vms are down
>>
>>
>>                                                             On Sat,
>>                                                             Apr 15,
>>                                                             2017 at
>>                                                             10:37 AM
>>                                                             FERNANDO
>>                                                             FREDIANI
>>                                                             <fernando.frediani at upx.com
>>                                                             <mailto:fernando.frediani at upx.com>>
>>                                                             wrote:
>>
>>                                                                 Hello
>>                                                                 Konstantin.
>>
>>                                                                 That
>>                                                                 doesn`t
>>                                                                 make
>>                                                                 much
>>                                                                 sense
>>                                                                 make
>>                                                                 a
>>                                                                 whole
>>                                                                 cluster
>>                                                                 depend
>>                                                                 on a
>>                                                                 single
>>                                                                 host.
>>                                                                 From
>>                                                                 what
>>                                                                 I
>>                                                                 know
>>                                                                 any
>>                                                                 host
>>                                                                 talk
>>                                                                 directly
>>                                                                 to
>>                                                                 NFS
>>                                                                 Storage
>>                                                                 Array
>>                                                                 or
>>                                                                 whatever
>>                                                                 other
>>                                                                 Shared
>>                                                                 Storage
>>                                                                 you have.
>>                                                                 Have
>>                                                                 you
>>                                                                 tested
>>                                                                 that
>>                                                                 host
>>                                                                 going
>>                                                                 down
>>                                                                 if
>>                                                                 that
>>                                                                 affects
>>                                                                 the
>>                                                                 other
>>                                                                 with
>>                                                                 the
>>                                                                 NFS
>>                                                                 mounted
>>                                                                 directlly
>>                                                                 in a
>>                                                                 NFS
>>                                                                 Storage
>>                                                                 array ?
>>
>>                                                                 Fernando
>>
>>                                                                 2017-04-15
>>                                                                 12:42
>>                                                                 GMT-03:00
>>                                                                 Konstantin
>>                                                                 Raskoshnyi
>>                                                                 <konrasko at gmail.com
>>                                                                 <mailto:konrasko at gmail.com>>:
>>
>>                                                                     In
>>                                                                     ovirt
>>                                                                     you
>>                                                                     have
>>                                                                     to
>>                                                                     attach
>>                                                                     storage
>>                                                                     through
>>                                                                     specific
>>                                                                     host.
>>
>>                                                                     If
>>                                                                     host
>>                                                                     goes
>>                                                                     down
>>                                                                     storage
>>                                                                     is
>>                                                                     not
>>                                                                     available.
>>
>>
>>                                                                     On
>>                                                                     Sat,
>>                                                                     Apr
>>                                                                     15,
>>                                                                     2017
>>                                                                     at
>>                                                                     7:31
>>                                                                     AM
>>                                                                     FERNANDO
>>                                                                     FREDIANI
>>                                                                     <fernando.frediani at upx.com
>>                                                                     <mailto:fernando.frediani at upx.com>>
>>                                                                     wrote:
>>
>>                                                                         Well,
>>                                                                         make
>>                                                                         it
>>                                                                         not
>>                                                                         go
>>                                                                         through
>>                                                                         host1
>>                                                                         and
>>                                                                         dedicate
>>                                                                         a
>>                                                                         storage
>>                                                                         server
>>                                                                         for
>>                                                                         running
>>                                                                         NFS
>>                                                                         and
>>                                                                         make
>>                                                                         both
>>                                                                         hosts
>>                                                                         connect
>>                                                                         to
>>                                                                         it.
>>                                                                         In
>>                                                                         my
>>                                                                         view
>>                                                                         NFS
>>                                                                         is
>>                                                                         much
>>                                                                         easier
>>                                                                         to
>>                                                                         manage
>>                                                                         than
>>                                                                         any
>>                                                                         other
>>                                                                         type
>>                                                                         of
>>                                                                         storage,
>>                                                                         specially
>>                                                                         FC
>>                                                                         and
>>                                                                         iSCSI
>>                                                                         and
>>                                                                         performance
>>                                                                         is
>>                                                                         pretty
>>                                                                         much
>>                                                                         the
>>                                                                         same,
>>                                                                         so
>>                                                                         you
>>                                                                         won`t
>>                                                                         get
>>                                                                         better
>>                                                                         results
>>                                                                         other
>>                                                                         than
>>                                                                         management
>>                                                                         going
>>                                                                         to
>>                                                                         other
>>                                                                         type.
>>
>>                                                                         Fernando
>>
>>                                                                         2017-04-15
>>                                                                         5:25
>>                                                                         GMT-03:00
>>                                                                         Konstantin
>>                                                                         Raskoshnyi
>>                                                                         <konrasko at gmail.com
>>                                                                         <mailto:konrasko at gmail.com>>:
>>
>>                                                                             Hi
>>                                                                             guys,
>>
>>                                                                             I
>>                                                                             have
>>                                                                             one
>>                                                                             nfs storage,
>>                                                                             it's
>>                                                                             connected
>>                                                                             through
>>                                                                             host1.
>>                                                                             host2
>>                                                                             also
>>                                                                             has
>>                                                                             access
>>                                                                             to
>>                                                                             it,
>>                                                                             I
>>                                                                             can
>>                                                                             easily
>>                                                                             migrate
>>                                                                             vms between
>>                                                                             them.
>>
>>                                                                             The
>>                                                                             question
>>                                                                             is
>>                                                                             -
>>                                                                             if
>>                                                                             host1
>>                                                                             is
>>                                                                             down
>>                                                                             -
>>                                                                             all
>>                                                                             infrastructure
>>                                                                             is
>>                                                                             down,
>>                                                                             since
>>                                                                             all
>>                                                                             traffic
>>                                                                             goes
>>                                                                             through
>>                                                                             host1,
>>                                                                             is
>>                                                                             there
>>                                                                             any
>>                                                                             way
>>                                                                             in
>>                                                                             oVirt
>>                                                                             to
>>                                                                             use
>>                                                                             redundant
>>                                                                             storage?
>>
>>                                                                             Only
>>                                                                             glusterfs?
>>
>>                                                                             Thanks
>>
>>
>>                                                                             _______________________________________________
>>                                                                             Users
>>                                                                             mailing
>>                                                                             list
>>                                                                             Users at ovirt.org
>>                                                                             <mailto:Users at ovirt.org>
>>                                                                             http://lists.ovirt.org/mailman/listinfo/users
>>                                                                             <http://lists.ovirt.org/mailman/listinfo/users>
>>
>>
>>
>>                                                             _______________________________________________
>>                                                             Users
>>                                                             mailing list
>>                                                             Users at ovirt.org
>>                                                             <mailto:Users at ovirt.org>
>>                                                             http://lists.ovirt.org/mailman/listinfo/users
>>                                                             <http://lists.ovirt.org/mailman/listinfo/users>
>>
>>
>>                                                         _______________________________________________
>>                                                         Users mailing
>>                                                         list
>>                                                         Users at ovirt.org
>>                                                         <mailto:Users at ovirt.org>
>>                                                         http://lists.ovirt.org/mailman/listinfo/users
>>                                                         <http://lists.ovirt.org/mailman/listinfo/users>
>>
>>
>>                                                     _______________________________________________
>>                                                     Users mailing list
>>                                                     Users at ovirt.org
>>                                                     <mailto:Users at ovirt.org>
>>                                                     http://lists.ovirt.org/mailman/listinfo/users
>>                                                     <http://lists.ovirt.org/mailman/listinfo/users>
>>
>>
>>
>
>
>     _______________________________________________
>     Users mailing list
>     Users at ovirt.org <mailto:Users at ovirt.org>
>     http://lists.ovirt.org/mailman/listinfo/users
>     <http://lists.ovirt.org/mailman/listinfo/users>
>
>
>
>
> -- 
> Adam Litke

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20170417/66580d98/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: image/png
Size: 33452 bytes
Desc: not available
URL: <http://lists.ovirt.org/pipermail/users/attachments/20170417/66580d98/attachment-0001.png>


More information about the Users mailing list