Hotfix Installation and Recovery

[titan31]

Hi,

We're looking to install some hotfixes this weekend, and I want a plan in place if this doesn't go well, as there's any issues, and we need to rollback. We're taking images of the VM where our Compute and Metadata are stored on, and doing a backup of the middle-tier server as that's physical. We've two options there, either a file level backup, or a clone of the image using an external tool.

How possible is it to actually rollback after installing hotfixes, and is there anything I need to be aware when taking the backups of the servers to ensure any recovery is easier?

Thanks

[JuanS_OCS]

Hi @titan31,

there is no such procedure as such, set in place by SAS. The hotfixes application is "irreversible".

Your best option is to run  a full SAS deployment backup before any big change (as a hotfix), and have a VM backup as you actually do.

If something goes wrong, you rollback the VMs and restore the status of the SAS deployment backup (specially interesting to keep aligned your WIP database, metadata and SAS Content Server).

For the future, perhaps you would like to create an image of the middle tier and virtualize that server, so you can tak snapshots as well. But again, your main concern will be just the alignment of the SAS Content Server repository with the SAS metadata and the data in WIP database.

[jklaverstijn · Accepted solution]

Rolling back from hotfixes is a much debated topic. Many hotfixes just replace binaries under the SASHome location and are easy to rollback with a filesystem backup. Others are more intricate. Eg when the middle tier is involved and redeploying the web apps is in order. or when the metadata repository or data model are touched.

Your best bet will be to recover from a complete backup of files, data, metadata and content server content. And bring down as many components (spawners, metadata server) as possible before applying your hotfixes. This depends on the hotfixes themselves.

The backup of all data stores must be in sync. The SAS Backup and Recovery utility provides a way of backing up a consistent set. So use this before starting your maintenance. Recovering from filesystem and a B&R recovery will allow you to roll back in case something hits the fan.

Hope this helps,

- Jan.