While setting up an instance of PostgreSQL on my home Kubernetes cluster, the issue of how to create a proper persistent volume came up. I wanted to use network-based storage for the pod primarily because I use FreeNAS and backing up the volume to S3 using a Cloud Sync Task would be trivially easy. Right away I ruled out using NFS for PostgreSQL storage over reliability and performance concerns, so that left iSCSI. But, in order to get the best performance out of an iSCSI volume I had to use a zvol (device) instead of a file, which meant that Cloud Sync Tasks couldn't be used.

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