On 2019-03-21 2:53 a.m., Ulrich Windl wrote: >>>> Digimer <[email protected]> schrieb am 20.03.2019 um 17:37 in Nachricht > <[email protected]>: >> Note; >> >> Cluster filesystems are amazing if you need them, and to be avoided if >> at all possible. The overhead from the cluster locking hurts performance >> quite a lot, and adds a non-trivial layer of complexity. > > Yes, that's the true challenge. It's sad that NFS might provide better > performance than a cluster filesystem will.
There's nothing sad about it. Shared filesystems like NFS and cluster file systems like GFS2 are designed to solve different problems. >> I say this as someone who has used dual-primary DRBD with GFS2 for >> many years. >> >> To expand on why you can't use something like ext4; Non-cluster-aware >> file systems expect all changes to the backing device to go through it. >> So there's no mechanism to tell the FS on one node that blocks have >> changed because of actions on another node. Likewise, they have no >> mechanism to coordinate sane and safe access to blocks. These mechanisms >> are exactly what makes a cluster FS what it is. >> >> digimer >> >> On 2019-03-20 11:52 a.m., Emmanuel Gelati wrote: >>> If you need to access from both nodes, you need to use primary/primary >>> mode in drbd >>> >>> Il giorno mer 20 mar 2019 alle ore 16:51 JCA <[email protected] >>> <mailto:[email protected]>> ha scritto: >>> >>> OK, thanks. Yet another thing I was not aware of in the clustering >>> world :-( >>> >>> On Wed, Mar 20, 2019 at 9:41 AM Valentin Vidic >>> <[email protected] <mailto:[email protected]>> wrote: >>> >>> On Wed, Mar 20, 2019 at 09:36:58AM -0600, JCA wrote: >>> > # pcs -f fs_cfg resource create TestFS Filesystem >>> device="/dev/drbd1" >>> > directory="/tmp/Testing" >>> > fstype="ext4" >>> >>> ext4 can only be mounted on one node at a time. If you need to >>> access >>> files on both nodes at the same time than a cluster filesystem >>> should >>> be used (GFS2, OCFS2). -- Digimer Papers and Projects: https://alteeve.com/w/ "I am, somehow, less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops." - Stephen Jay Gould _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
