PersistentVolumes and related operations considerations | HCL Digital Experience
This topic provides details covering the PersistentVolumes (PVs) and related operations considerations in storing data for DX 9.5 stateful applications.
Digital Experience 9.5 container-based stateful applications (DX 9.5 Core, Digital Asset Management, and Persistence) require PersistentVolumes (PVs) to store their data. Refer to the Deploy DX 9.5 applications to container platforms using Helm topic for a description of the DX 9.5 Applications details.
As Kubernetes and OpenShift Pods do not have their own persistent file storage, the use of PVs is a must. For more information on PVs, consult the Kubernetes documentation.
ReadWriteOnce
(RWO) persistent
volumes for all applications, you will not be able to scale them up to multiple
Pods.Core
- Profiles (called
wp_profile
andcw_profile
) - Logs
- Transaction logs
While the profile needs to be shared between all DX 9.5 Core Pods, the logs and
transaction logs are per Pod and not shared. This means that the persistent volume
used for the profile must be ReadWriteMany
(RWX).
The persistent volumes used for logs and transaction logs are established as
ReadWriteOnce
(RWO) for proper operations performance.
For example, in a DX 9.5 Core deployment:
To deploy one Core Pod, 3 PVs will be needed. To deploy two Core Pods, the number of required PVs increases by two, resulting in 5 PVs needed, since the second Pod shares the existing profile PV with the first Pod, but requires its own log and transaction log PVs.
# Formula to calculate PV count
n(PV) = 1 + m(Core Pods) * 2
# E.g. for 3 Pods: 1 + 3 * 2 = 7 PVs
In typical operations, the persistent volumes for logs and transaction logs are relatively small.
Digital Asset Management
The Digital Asset Management (DAM) application requires one (1) PV for storing binary
asset data. This persistent volume is shared between all Digital Asset Management
Pods. The PV used must be ReadWriteMany (RWX)
.
Persistence
Persistence consists of at least two Pods. One which acts as a read/write primary node, and at least one that acts as a read-only fallback.
All Persistence Pods work with ReadWriteOnce
(RWO) persistent
volumes, since there is no sharing of storage between the Pods.
Therefore, the minimum required amount of PVs for Persistence is 2.
Remote Search
Remote Search requires 1 persistent volume for storing the profile (called
prs_profile
) with the type ReadWriteOnce
(RWO).
Remote Search is limited to only one Pod, therefore, requires one PV for that Pod.
Refer to Networking configuration for next steps.