If you're in a tight VM and are running Redis inside it, as opposed to a separate VM / cluster, you need an embedded DB, not Redis.
You can use the ancient BerkeleyDB which is supported everywhere for last like 30 years. Or a more recent LevelDB. Or even SQLite which is plenty fast on simple queries.
You'll have to tolerate the high latency of safely writing tings to a block device, compared to RAM. If your load is mostly reads, it should be OK.
Comments
If you're in a tight VM and are running Redis inside it, as opposed to a separate VM / cluster, you need an embedded DB, not Redis.
You can use the ancient BerkeleyDB which is supported everywhere for last like 30 years. Or a more recent LevelDB. Or even SQLite which is plenty fast on simple queries.
You'll have to tolerate the high latency of safely writing tings to a block device, compared to RAM. If your load is mostly reads, it should be OK.