Hi Dan, ZFS without sync would be very much identical to ext2/ext4 without journals or XFS with barriers disabled. The ARC cache in ZFS is awesome but disbaling sync on ZFS is a very high risk (using ext4 with kvm-mode unsafe would be similar I think).
Also, ZFS only works as expected with scheduler set to noop as it is optimized to consume whole, non-shared devices. Just my 2 cents ;-) Kevin Am Mo., 12. Nov. 2018 um 15:08 Uhr schrieb Dan van der Ster < d...@vanderster.com>: > We've done ZFS on RBD in a VM, exported via NFS, for a couple years. > It's very stable and if your use-case permits you can set zfs > sync=disabled to get very fast write performance that's tough to beat. > > But if you're building something new today and have *only* the NAS > use-case then it would make better sense to try CephFS first and see > if it works for you. > > -- Dan > > On Mon, Nov 12, 2018 at 3:01 PM Kevin Olbrich <k...@sv01.de> wrote: > > > > Hi! > > > > ZFS won't play nice on ceph. Best would be to mount CephFS directly with > the ceph-fuse driver on the endpoint. > > If you definitely want to put a storage gateway between the data and the > compute nodes, then go with nfs-ganesha which can export CephFS directly > without local ("proxy") mount. > > > > I had such a setup with nfs and switched to mount CephFS directly. If > using NFS with the same data, you must make sure your HA works well to > avoid data corruption. > > With ceph-fuse you directly connect to the cluster, one component less > that breaks. > > > > Kevin > > > > Am Mo., 12. Nov. 2018 um 12:44 Uhr schrieb Premysl Kouril < > premysl.kou...@gmail.com>: > >> > >> Hi, > >> > >> > >> We are planning to build NAS solution which will be primarily used via > NFS and CIFS and workloads ranging from various archival application to > more “real-time processing”. The NAS will not be used as a block storage > for virtual machines, so the access really will always be file oriented. > >> > >> > >> We are considering primarily two designs and I’d like to kindly ask for > any thoughts, views, insights, experiences. > >> > >> > >> Both designs utilize “distributed storage software at some level”. Both > designs would be built from commodity servers and should scale as we grow. > Both designs involve virtualization for instantiating "access virtual > machines" which will be serving the NFS and CIFS protocol - so in this > sense the access layer is decoupled from the data layer itself. > >> > >> > >> First design is based on a distributed filesystem like Gluster or > CephFS. We would deploy this software on those commodity servers and mount > the resultant filesystem on the “access virtual machines” and they would be > serving the mounted filesystem via NFS/CIFS. > >> > >> > >> Second design is based on distributed block storage using CEPH. So we > would build distributed block storage on those commodity servers, and then, > via virtualization (like OpenStack Cinder) we would allocate the block > storage into the access VM. Inside the access VM we would deploy ZFS which > would aggregate block storage into a single filesystem. And this filesystem > would be served via NFS/CIFS from the very same VM. > >> > >> > >> Any advices and insights highly appreciated > >> > >> > >> Cheers, > >> > >> Prema > >> > >> _______________________________________________ > >> ceph-users mailing list > >> ceph-users@lists.ceph.com > >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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