Local Redundancy
Definition
Local redundancy involves storing multiple copies of data within a single data center, safeguarding against hardware failures and ensuring data integrity.
Use Cases
- Microsoft: Durable storage for blobs and files where data residency stays within a single Azure region and cost is prioritized over cross-zone resilience. — Customers can choose Azure Storage with Locally Redundant Storage (LRS), which keeps multiple copies of data within a single datacenter in a region to protect against drive/node failures. (Lower storage cost compared to zone- or geo-redundant options while still protecting against common hardware failures inside the datacenter.)
- Dropbox: Protecting stored files against disk and server failures within a single facility as part of a broader durability strategy. — Dropbox has publicly described using replication/erasure coding across many storage nodes within a site to tolerate hardware failures; this is a form of local redundancy at the facility level, typically combined with additional replication across sites for higher resilience. (Improved durability and availability during routine hardware failures, reducing the chance that a single disk/server issue impacts customer access.)
Provider Equivalents
- Azure: Azure Storage - Locally Redundant Storage (LRS)
Frequently Asked Questions
- What's the difference between Local Redundancy and Zone Redundancy?
- Local redundancy keeps multiple copies of your data in one physical location (one datacenter). It protects you from common hardware problems like a disk or server failing. Zone redundancy spreads copies across multiple datacenters (availability zones) in the same region, so it can keep working even if an entire datacenter goes down.
- When should I use Local Redundancy?
- Use local redundancy when you want protection from normal hardware failures but you can tolerate an outage if the whole datacenter has a problem. It’s a good fit for dev/test environments, non-critical backups that are also stored elsewhere, caches, or workloads where cost is more important than surviving a datacenter outage.
- How much does Local Redundancy cost?
- Local redundancy is usually the lowest-cost durability option because it doesn’t replicate across zones or regions. Pricing depends on the storage class/tier (hot/cool/archive), how much data you store (GB-month), operations (reads/writes/list), and data transfer. Options that add zone or geographic replication typically cost more because they store additional copies in more places.
Category: data
Difficulty: intermediate
Related Terms
See Also