Az104 — Azure Storage/Data Replication
· Locally redundant storage (LRS) copies your data three times across separate racks of hardware in a datacenter, inside one region.
o Even if there’s a hardware failure, or if maintenance work is happening in the datacenter, this replication type ensures data is available for use.
o LRS doesn’t protect you from a datacenter-wide outage.
o If the datacenter goes down, you could lose your data.
· Geographically redundant storage (GRS), your data is copied three times within one region, and three times in a secondary region that’s paired with it.
o This way, if your primary region is experiencing an outage, your secondary region is available for use.
· With geo-redundant storage (GRS), your secondary region isn’t available for read access until the primary region fails.
o If you want to read from the secondary region, even if the primary region hasn’t failed, use RA-GRS for your replication type.
· Zone-redundant storage (ZRS) copies your data in three storage clusters in a single region.
o Each cluster is in a different physical location and is considered as a single availability zone.
o Each cluster uses its own separate utilities for things like networking and power.
o If one datacenter is experiencing outage, your data remains accessible from another availability zone in the same Azure region.
o Because all availability zones are in a single region, ZRS can’t protect your data from a regional level outage.
· Geo-zone-redundant storage (GZRS) combines the high availability benefits of ZRS with GRS.
o With this replication type, your data is copied across three availability zones in one region.
o Data is also replicated three times to another secondary region that’s paired with it.
o This way, your zone-redundant data is also secure from regional level outage.
· Read-access geo-zone-redundant storage (RA-GZRS) uses the same replication method as GZRS but lets you read from the secondary region.
o If you want to read the data that’s replicated to the secondary region, even if your primary isn’t experiencing downtime, use RA-GZRS for your replication type.
