SQL Server - Upgrade
PaaS upgrade workflow
Request
The upgrade of a SQL Server PaaS instance is the responsibility of cegedim.cloud. Requests must be submitted via an ITCare ticket, specifying a preferred time window for the operation.
Please indicate if the upgrade must be performed outside of business hours, to allow for proper RFC planning.
It is strongly recommended to first perform the upgrade in a non-production environment, to validate compatibility of the entire process with the client's technical and application constraints.
Upgrades of SQL Server clusters older than version 2016 are not supported by cegedim.cloud.
This limitation is due to major changes introduced in the SQL Server engine starting with version 2016, particularly regarding AlwaysOn features and the deprecation of legacy components.
Major version upgrades (e.g., from SQL Server 2019 to 2022) require a different approach, namely the full reprovisioning of the environment. In this case, a new PaaS instance must be provisioned with the target version, followed by a manual migration of databases.
This process only covers the application of Cumulative Updates (CU) published by Microsoft. These updates contain security, stability, and performance fixes for SQL Server.
Process
The upgrade process involving Cumulative Updates follows these steps:
Snapshot of virtual machines (to enable rollback in case of failure)
Full backup of customer databases using Rubrik
Installation of SQL Server Cumulative Updates (official Microsoft patches)
Server reboot to apply the updates
Integrity checks on databases and review of error logs
For AlwaysOn clusters:
Secondary nodes are patched first
A manual failover to the secondary node is performed prior to updating the primary
Controlled reboot of the updated node
The process is repeated for remaining nodes
Impacts
Applying Cumulative Updates can lead to temporary service interruptions or changes in application behavior.
Points to consider:
Temporary unavailability of SQL Server during reboot
Risk of functional regressions due to internal behavior changes in CU
Possible rollback required if installation fails
Potential risks:
Failure to rejoin the AlwaysOn cluster
Data corruption if backups are invalid
Broken application dependencies due to changes introduced by the CU
Estimated Duration
The duration of an upgrade depends on several factors, including the data volume to be backed up and the deployment mode (standalone vs AlwaysOn).
Estimated durations:
Standalone instance with low volume: ~1 hour
AlwaysOn cluster with failover: ~2 to 3 hours
These durations are indicative only and should be adjusted according to the specific constraints of the target environment (I/O, load, network latency, etc.).
Operating System Updates
Windows Server updates are performed exclusively during scheduled "Patch Parties"—maintenance windows during which critical security and stability patches are applied in a coordinated manner, in line with cegedim.cloud's maintenance schedule.
These operations are outside the scope of the SQL Server upgrade. If an OS version change is required, the following steps must be taken:
Request reprovisioning of a PaaS instance with the new OS version via ITCare
Perform a manual migration of the databases to the new instance
In-place upgrades of the operating system are not supported.
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