[ovirt-users] storage redundancy in Ovirt

[Konstantin Raskoshnyi]

"Corner cases"?
I tried to simulate crash of SPM server and ovirt kept trying to
reistablished connection to the failed node.


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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