[ovirt-users] storage redundancy in Ovirt

[Dan Yasny]

On Sun, Apr 16, 2017 at 11:13 PM, Konstantin Raskoshnyi <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> wrote:
>
>> On Sun, Apr 16, 2017 at 7:29 AM, Nir Soffer <nsoffer at redhat.com> wrote:
>>
>>> On Sun, Apr 16, 2017 at 2:05 PM Dan Yasny <dyasny at redhat.com> wrote:
>>>
>>>>
>>>>
>>>> On Apr 16, 2017 7:01 AM, "Nir Soffer" <nsoffer at redhat.com> wrote:
>>>>
>>>> On Sun, Apr 16, 2017 at 4:17 AM Dan Yasny <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> 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> 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
>>>>>>> >:
>>>>>>>
>>>>>>>> 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> 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>:
>>>>>>>>>
>>>>>>>>>> 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
>>>>>>>>>>
>>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>>
>>>>>>>
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