PostgreSQL volume support default value might be switched to False

[Denis M.]

Many installations create database clusters or instances on network file systems. Sometimes this is done directly via NFS, or by using a Network Attached Storage (NAS) device that uses NFS internally. PostgreSQL does nothing special for NFS file systems, meaning it assumes NFS behaves exactly like locally-connected drives (DAS, Direct Attached Storage). If client and server NFS implementations have non-standard semantics, this can cause reliability problems (see http://www.time-travellers.org/shane/papers/NFS_considered_harmful.html). Specifically, delayed (asynchronous) writes to the NFS server can cause reliability problems; if possible, mount NFS file systems synchronously (without caching) to avoid this. Also, soft-mounting NFS is not recommended. (Storage Area Networks (SAN) use a low-level communication protocol rather than NFS.)

Since cinder can do remote volume attachment, it'll be much safer, if we'd switch default value for postgresql volume_support to False. And let Trove deployer explicitly say that postgresql should work with volumes.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/229270

[Amrith Kumar (amrith)]

I'm marking this bug as Invalid (in preference to opinion) because the argument being made here could equally be well made for any database.

The default (except for something like Redis which by default is intended to be a cache) of True makes sense for most databases.

Also, changing the default to false at this time could have implications for all deployments that have already deployed Trove with PostgreSQL!

[OpenStack Infra (hudson-openstack)]

Change abandoned by Craig Vyvial (<email address hidden>) on branch: master
Review: https://review.openstack.org/229270
Reason: Abandoning this review as no activity for a month and the fact that we've determined this is bug is invalid.