Re: [ovirt-users] storage redundancy in Ovirt

On Sun, Apr 16, 2017 at 11:19 PM, Konstantin Raskoshnyi < konrasko(a)gmail.com&gt; 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(a)gmail.com&gt; wrote: > >> On Sun, Apr 16, 2017 at 11:15 PM, Konstantin Raskoshnyi < >> konrasko(a)gmail.com&gt; 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(a)gmail.com&gt; wrote: >>> >>>> On Sun, Apr 16, 2017 at 11:13 PM, Konstantin Raskoshnyi < >>>> konrasko(a)gmail.com&gt; 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(a)gmail.com&gt; wrote: >>>>> >>>>>> On Sun, Apr 16, 2017 at 7:29 AM, Nir Soffer <nsoffer(a)redhat.com&gt; >>>>>> wrote: >>>>>> >>>>>>> On Sun, Apr 16, 2017 at 2:05 PM Dan Yasny <dyasny(a)redhat.com&gt; >>>>>>> wrote: >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Apr 16, 2017 7:01 AM, "Nir Soffer" <nsoffer(a)redhat.com&gt; wrote: >>>>>>>> >>>>>>>> On Sun, Apr 16, 2017 at 4:17 AM Dan Yasny <dyasny(a)gmail.com&gt; >>>>>>>> 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(a)gmail.com&gt; 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(a)upx.com&gt; 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(a)gmail.com&gt;: >>>>>>>>>>> >>>>>>>>>>>> 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(a)upx.com&gt; 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(a)gmail.com&gt;: >>>>>>>>>>>>> >>>>>>>>>>>>>> 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(a)ovirt.org >>>>>>>>>>>>>> http://lists.ovirt.org/mailman/listinfo/users >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> Users mailing list >>>>>>>>>> Users(a)ovirt.org >>>>>>>>>> http://lists.ovirt.org/mailman/listinfo/users >>>>>>>>>> >>>>>>>>>> >>>>>>>>> _______________________________________________ >>>>>>>>> Users mailing list >>>>>>>>> Users(a)ovirt.org >>>>>>>>> http://lists.ovirt.org/mailman/listinfo/users >>>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> Users mailing list >>>>>>>> Users(a)ovirt.org >>>>>>>> http://lists.ovirt.org/mailman/listinfo/users >>>>>>>> >>>>>>>> >>>>>>>>