Jeter-work's questions

I am going to repurpose 5 servers from their previous use as computational servers to be a KVM system. This will become my sandbox for testing patches and for testing new software, configuration changes, etc. I want to use GlusterFS to create a storage pool for the KVM guests and as a restore location to enable easier restores from tape (i.e. restore a LUN to sandbox, move over the files to production). Ultimately I plan to test how GlusterFS can fulfill our storage needs.

Reading through the different implementations on GlusterFS docs page, I have questions regarding the type of volume to set up.

Five servers are each 4 processor, 1TB RAM, 50TB SAS RAID5, 4x10G CNA. Plus a sixth smaller server that would not be part of the Gluster setup.

Two questions:

1. Can these servers serve as a KVM system, and have the GlusterFS underneath? Assuming, two virtual disks presented by the underlying hardware RAID system. First, a small one (two disks) for the OS and then the rest (14 disks) for Gluster. The systems are monsters, I think I can build something of a hyperconverged network from these 5.

2. Assuming #1 is true, how do I choose between "Dispersed Distributed" and "Dispersed"? I have RAID5 on the systems now. I may upgrade to RAID6 if the cards accept it. So the redundancy afforded by Dispersed volume is really more for protection against losing a whole server or two due to other issues.

42TB LUN, formatted in XFS and shared via NFS was reported 'unavailable' by customers. In the end I was forced to restart the file server. The XFS LUN won't mount until it is repaired, and to repair I need to mount it so the log will replay and commit the uncommitted changes. In the past, I've learned that dumping the log and running the repair results in loss of filenames for a portion of the files and folders in the LUN. 42 TB and potentially hundreds of thousands of files. Loss of filenames equates to data loss.

I have a backup. Restoring will require gathering resources. I think there's roughly 30TB of data in that LUN that I need to restore and copy back into place. So I need 30 TB of free space, which is not readily available.

Is there another way of forcing XFS to mount in order to replay those logs and commit the changes?

This is the third time I've had a LUN 'freeze' on me and be reported as xfs corrupted in the logs and been forced to reboot the server to bring it back online. XFS seems to have a solid reputation. It has been around for a significant amount of time. And it is the default for the file server's OS (RHEL7). Have I got some terrible error in my configuration that is killing these LUNs?

SAN presents LUN, mounted nodev,nosuid,nofail on file server. File server shares to workstations which mount the share as synchronous. Is there something in this combination that would hang the file server?