Litestream vs GCP regionally replicated disks

[broccolihighkicks]

How does Litestream compare with using a GCP regional disk + hourly incremental snapshots?

https://cloud.google.com/compute/docs/disks/repd-failover

With regional persistent disks, data is automatically replicated to two zones in a region.
If both replicas are available, a write is acknowledged back to a VM when it is durably persisted in both replicas.

If my primary VM goes down, I think the replica disk in the other zone will have a full SQLite file that is recoverable? (ignoring any replication issues or non committed transactions).

[yanc0]

Litestream is more of a logical replication (WAL) and Regional disks are physical replication (sectors).

1. GCP multizonal disks are only available on GCP as far a I know.
2. An entire region can burn (with your regional disks inside) #OVH
3. Technology can fail and will fail, data durability is never 100% even for objects storage

If you can use both, you should as there is no excuse to avoid them on GCP.

[benbjohnson]

Litestream is physical replication as well as it copies raw WAL frames. Logical replication would be if it replicated SQL statements.

I agree with all the other points though. It seems like regional persistent disks are probably a good option although I'm not sure what their performance looks like. Network connected disks can have higher latency or more limited IOPS as compared to a local ephemeral disk so that may be a trade-off.

Ultimately, trusting GCP alone can be dangerous as @yanc0 mentioned. I would either use Litestream as a backup to regional persistent disks or daily/hourly backups to somewhere off-site.

[yanc0]

You're right, logical replication is not really what I meant. But there is a difference between dealing with a application data format (WAL) specified by a software (SQLite) inside an operation system context and disk sectors which are situated at the lowest level you can find on the computer. I think that we need a third word to distinguish WALs from blocks. Logical / ....... / Physical.