[ovirt-users] storage redundancy in Ovirt

Mon Apr 17 03:15:37 UTC 2017

Fence agent under each node?

On Sun, Apr 16, 2017 at 8:14 PM Dan Yasny <dyasny at gmail.com> wrote:

> 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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>>>>>
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