I tried creating two PV's of 10Gi both pointing at the same NFS of 1TB. I also create 2 PVCs for the same StorageClass also of 10Gi.
The problem is that when I add a file to on the the PVs the same file is present on the other PV. What I would like to be able to do it to create to separate 'partitions' (or locaigical separation) so that one PV does not share the data of the other PV - is this possible? On Monday, August 1, 2016 at 9:52:41 AM UTC+2, Tim Hockin wrote: > > YOu can create multiple PVs with the same NFS export, as long as that > is acceptable to you :) > > On Mon, Aug 1, 2016 at 12:51 AM, Qian Zhang <zhq5...@gmail.com > <javascript:>> wrote: > > Got it, thanks Tim! > > > > BTW, is there any best practice to use PV of NFS type? E.g., there is an > NFS > > server which has only one export, should admin only create 1 PV for it? > Or > > it is also OK to create multiple PVs? > > > > > > Thanks, > > Qian Zhang > > > > On Mon, Aug 1, 2016 at 3:32 PM, 'Tim Hockin' via Containers at Google > > <google-c...@googlegroups.com <javascript:>> wrote: > >> > >> If your NFS system supports that, that is one way ti could be done, > yes. > >> > >> On Mon, Aug 1, 2016 at 12:13 AM, Qian Zhang <zhq5...@gmail.com > <javascript:>> wrote: > >> > I am curious how the storage system behind us does the enforcement, > >> > e.g., > >> > will we let NFS server know the capacity of PV is 1GB, and NFS server > >> > can > >> > guarantee the pod using that PV can not write more than 1GB? > >> > > >> > > >> > Thanks, > >> > Qian Zhang > >> > > >> > On Mon, Aug 1, 2016 at 3:00 PM, 'Tim Hockin' via Containers at Google > >> > <google-c...@googlegroups.com <javascript:>> wrote: > >> >> > >> >> Nobody enforces it yet (well, WE don't, but the storage system > behind > >> >> us might). It's a way to match user needs (PVC) to available > >> >> resources (PV). > >> >> > >> >> > why does user need to define the PVC's capacity when creating the > >> >> > PVC? > >> >> > >> >> If the user needs 100GB and I give them a PV with 2 GB, they will > not > >> >> be happy. They have to specify how much they nee so we can bind (or > >> >> provision) a PV for them. > >> >> > >> >> On Sun, Jul 31, 2016 at 11:54 PM, Qian Zhang <zhq5...@gmail.com > <javascript:>> > >> >> wrote: > >> >> > Yeah, actually I am also a bit confused about the capacity user > >> >> > defined > >> >> > in > >> >> > PV and PVC, who will be responsible for enforcing it? E.g., I have > an > >> >> > NFS > >> >> > server which has 10GB free, and I create a PV (1GB) and PVC (1GB), > >> >> > and > >> >> > create a pod uses that PVC. So in the pod, can I only write 1GB > into > >> >> > the > >> >> > mounted NFS directory? If so, who enforces it? > >> >> > > >> >> > And if a PV can only be used by a single PVC, why does user need > to > >> >> > define > >> >> > the PVC's capacity when creating the PVC? I think we should not > ask > >> >> > user > >> >> > to > >> >> > define it, i.e., all the capacity of the PV should be used. > >> >> > > >> >> > > >> >> > > >> >> > Thanks, > >> >> > Qian Zhang > >> >> > > >> >> > On Mon, Aug 1, 2016 at 2:45 PM, 'Tim Hockin' via Containers at > Google > >> >> > <google-c...@googlegroups.com <javascript:>> wrote: > >> >> >> > >> >> >> A PV uses a single backing medium, but multiple PVs might share > that > >> >> >> medium. Consider "thin" block devices which allocate actual > space > >> >> >> on > >> >> >> demand. You might over-commit your storage system. Consider NFS > >> >> >> which can have multiple exports on the same filesystem. You > might > >> >> >> over-commit your NFS server. > >> >> >> > >> >> >> Not saying it's a great idea, just that it is possible. > >> >> >> > >> >> >> On Sun, Jul 31, 2016 at 11:40 PM, Qian Zhang <zhq5...@gmail.com > <javascript:>> > >> >> >> wrote: > >> >> >> > Thanks Tim! So a PV can only be used by a single PVC no matter > >> >> >> > what > >> >> >> > its > >> >> >> > type > >> >> >> > is. > >> >> >> > > >> >> >> > And can you please clarify a bit about "You can make a PV that > >> >> >> > uses > >> >> >> > the > >> >> >> > same > >> >> >> > backing medium, if the driver allows it"? I do not quite > >> >> >> > understand > >> >> >> > about > >> >> >> > it, I think a PV should always use a single backing medium > rather > >> >> >> > than > >> >> >> > multiple, right? > >> >> >> > > >> >> >> > > >> >> >> > Thanks, > >> >> >> > Qian Zhang > >> >> >> > > >> >> >> > On Mon, Aug 1, 2016 at 2:34 PM, 'Tim Hockin' via Containers at > >> >> >> > Google > >> >> >> > <google-c...@googlegroups.com <javascript:>> wrote: > >> >> >> >> > >> >> >> >> A PersistentVolume (PV) is an atomic abstraction. You can not > >> >> >> >> subdivide it across multiple claims. You can make a PV that > uses > >> >> >> >> the > >> >> >> >> same backing medium, if the driver allows it. E.g. consider > NFS. > >> >> >> >> If > >> >> >> >> your NFS server has 150 GB free, nothing stops you from making > 2 > >> >> >> >> PVs > >> >> >> >> each of size 100GB. We can't validate that. It might be bad > for > >> >> >> >> your > >> >> >> >> users, but that is a decision you have to make as a cluster > >> >> >> >> admin. > >> >> >> >> > >> >> >> >> On Sun, Jul 31, 2016 at 11:31 PM, Qian Zhang > >> >> >> >> <zhq5...@gmail.com <javascript:>> > >> >> >> >> wrote: > >> >> >> >> > Hi, > >> >> >> >> > > >> >> >> >> > If I have one persistent volume (100GB) created in > Kubernetes, > >> >> >> >> > can > >> >> >> >> > I > >> >> >> >> > create > >> >> >> >> > two persistent volume claims (50GB for each) to use this > >> >> >> >> > persistent > >> >> >> >> > volume? > >> >> >> >> > It seems I can not do it with NFS type of persistent volume, > >> >> >> >> > i.e., > >> >> >> >> > once > >> >> >> >> > an > >> >> >> >> > NFS persistent volume is partially used by a persistent > volume > >> >> >> >> > claim, > >> >> >> >> > it > >> >> >> >> > can > >> >> >> >> > not be used by any other persistent volume claims even it > still > >> >> >> >> > has > >> >> >> >> > free > >> >> >> >> > capacity. But I am not sure if the other type of persistent > >> >> >> >> > volumes > >> >> >> >> > (Ceph, > >> >> >> >> > Glusterfs, etc.) have the same behavior. > >> >> >> >> > > >> >> >> >> > -- > >> >> >> >> > You received this message because you are subscribed to the > >> >> >> >> > Google > >> >> >> >> > Groups > >> >> >> >> > "Containers at Google" group. > >> >> >> >> > To unsubscribe from this group and stop receiving emails > from > >> >> >> >> > it, > >> >> >> >> > send > >> >> >> >> > an > >> >> >> >> > email to google-contain...@googlegroups.com <javascript:>. > >> >> >> >> > To post to this group, send email to > >> >> >> >> > google-c...@googlegroups.com <javascript:>. > >> >> >> >> > Visit this group at > >> >> >> >> > https://groups.google.com/group/google-containers. > >> >> >> >> > For more options, visit https://groups.google.com/d/optout. > >> >> >> >> > >> >> >> >> -- > >> >> >> >> You received this message because you are subscribed to a > topic > >> >> >> >> in > >> >> 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