On Sun, Oct 30, 2016 at 12:02 PM, Mike (maillinglists) <[email protected]> wrote:
> Hi guys, > > There have been a few related questions already that I could find, but I > did not find anything relating to my specific use case. > > Currently it is not possible to mix local storage with shared storage in > the same datacenter. > The reason seems to be because of the storage pool manager (SPM). > This is a role in the datacenter provided to one specific host. > > While I understand that this makes having local storage impossible, I > believe there is a use case to have local storage in a shared storage > datacenter. > Indeed, this is one of the more appealing use cases. There are others s well. > Consider the following: > I have a few applications that require 1 milli second latency and at most > 2 milli second. > For read, write or both? > That is not consistenly achievable with shared storage, to that end I > added flash storage to a few hypervisors. > You could have flash on your shared storage. > About 5% of my servers require this and are not that resource hungry to > require a dedicated physical server. > That same 5% also has no requirement to be migrated if a host fails. > > So in short I have 5 heavy hosts running ovirt with a shared storage > domain on NFS for 95% of my servers. > All running fine, but I am now unable to run my remaining 5%. > Perhaps, if there are no HA requirements, those VMs with local domain needs can be in their own DC, a local one? If it's just 5%, shouldn't be much of an effort? > > To finish up my summary I have been testing various virtualization > technologies, like VmWare and Hyper-V. > They allow such configurations as I mentioned. > > I already had some chat on irc with various guys and they suggested that I > put this on the mailing list, so here goes. > > My suggestion would be to evoluate from SPM to SDM. > Easier said than done... We have worked on this for quite some time, it's not as easy as one might think. > SDM stands for Storage Domain Manager. > This would create the possibility to have all nodes in the datacenter > participate in the storage handling. > A extra benefit would be that local storage could be added. > > What do you think? > There are other use cases we think flash on the host can be used, some may be of use for your use case. For example, dm-cache[1]. We are still looking at this. I think Gluster already can make use it for cache, for example. Y. [1] https://people.redhat.com/mskinner/rhug/q1.2016/dm-cache.pdf > > Thanks for reading. > > Kind regards, > Mike van Goor > _______________________________________________ > Users mailing list > [email protected] > http://lists.ovirt.org/mailman/listinfo/users >
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