Virtual Data Optimizer (VDO) volumes are comprised of up to 8096 slabs. The default slab size is 2GB, which limits VDO volumes to a maximum physical size of 16TB, and a maximum supported logical size of 160TB. This means that creating a VDO volume on a physical device that is larger than 16TB fails.

To work around this issue, specify a larger slab size at VDO volume creation.

When bricks are configured asymmetrically, and a logical cache volume is configured, the cache volume is attached to only one brick. This is because the current implementation of asymmetric brick configuration creates a separate volume group and thin pool for each device, so asymmetric brick configurations would require a cache volume per device. However, this would use a large number of cache devices, and is not currently possible to configure using Cockpit.

To work around this issue, first remove any cache volumes that have been applied to an asymmetric brick set.

# lvconvert --uncache volume_group/logical_cache_volume

Then, follow the instructions in Configuring a logical cache volume to create a logical cache volume manually.

During RHHI for Virtualization setup, two separate network interfaces are required to set up Red Hat Gluster Storage. After storage configuration is complete, the hosted engine is deployed and the host is added to the engine as a managed host. During host deployment, the storage network is altered, and BOOTPROTO=dhcp is removed. This means that the storage network does not have IP addresses assigned automatically, and is not available after the hosted engine is deployed.

To work around this issue, add the line BOOTPROTO=dhcp to the network interface configuration file for your storage network after deployment of the hosted engine is complete.

The vdsm service makes various configuration changes after Red Hat Virtualization is first installed. One such change makes multipath entries for devices visible on RHHI for Virtualization, including local devices. This causes issues on hosts that are updated or rebooted before the RHHI for Virtualization deployment process is complete.

To work around this issue, add all devices to the multipath blacklist:

When the profiling window is opened, NFS profile statistics are queried even when a volume does not have any NFS clients or NFS access enabled. This results in the brick profile UI reporting the following error: Could not fetch brick profile stats.

To work around this issue, select a brick from the profile information window and refresh details to see profiling details for the brick.

When a virtualization host is upgraded to any Red Hat Hyperconverged infrastructure for Virtualization 1.5 release, the performance profile for the virt group is not updated with parameters added during development. This means that upgraded deployments are not optimally tuned for most use cases. To work around this issue, add the following options to the /var/lib/glusterd/groups/virt file on each server, or manually set these options on your upgraded volumes.

cluster.choose-local=off
client.event-threads=4
server.event-threads=4
performance.client-io-threads=on

Run the following command for all volumes to apply the updated virt profile.

# gluster volume set <volname> group virt

When you attempt to configure a logical volume cache for a thickly provisioned volume using the Cockpit UI, the deployment fails. You can manually configure a logical volume cache after deployment by adding a faster disk to your volume group using the following procedure. Note that device names are examples.