Replication options – Implement and manage storage – AZ-104 Study Guide

Replication options

When you create a storage account, you can also specify how your data will be replicated for redundancy and resistance to failure. There are four options, as described in Table 2-2.

TABLE 2-2 Storage account replication options

Replication TypeDescription
Locally redundant storage (LRS)Makes three synchronous copies of your data within a single datacenter. Available for General-Purpose or Blob Storage accounts, at both the Standard and Premium Performance tiers.
Zone redundant storage (ZRS)Makes three synchronous copies to three separate availability zones within a single region.Available for General-Purpose V2 storage accounts only, at the Standard Performance tier only. Also available for Block Blob Storage and File Storage accounts.
Geographically redundant storage(GRS)This is the same as LRS (three local synchronous copies), plus three additional asynchronous copies to a second Azure region hundreds of miles awayfrom the primary region. Data replication typically occurs within 15 minutes, although no SLA is provided.Available for General-Purpose or Blob Storage accounts, at the Standard Performance tier only.
Read access geographically redundant storage(RA-GRS)This has the same capabilities as GRS, plus you have read-only access to the data in the secondary data center.Available for General-Purpose or Blob Storage accounts, at the Standard Performance tier only.
Geographically zoneredundant storage (GZRS)This is the same as ZRS (three synchronous copies across multiple availabilityzones in the selected region), plus three additional asynchronous copies to a different Azure region hundreds of miles away from the primary region. Data replication typically occurs within 15 minutes, although no SLA is provided.Available for General-Purpose v2 storage accounts only, at the Standard Performance tier only.
Read access geographically zone redundant storage (RA-GZRS)This has the same capabilities as GZRS, plus you have read-only access to thedata in the secondary data center.Available for General-Purpose V2 storage accounts only, at the Standard Performance tier only.
NOTE  REPLICATION OPTIONS
These replication options control the level of durability and availability of the storage account.
When the entire datacenter is unavailable, LRS would incur an outage. If the primary region is unavailable, both the LRS and ZRS options would incur an outage, but the GRS and GZRS options would still provide the secondary region that takes care of the requests during the outage. However, not all the replication options are available in all regions. You can find sup- ported regions with these replication options at https://learn.microsoft.com/en-us/azure/storage/common/storage-redundancy.

NOTE SPECIFYING REPLICATION AND PERFORMANCE TIER SETTINGS

When creating a storage account via the Azure portal, the replication and performance tier options are specified using separate settings. When creating an account using Azure Power- Shell, the Azure CLI, or via a template, these settings are combined within the SKU setting.

For example, to specify a Standard storage account using locally redundant storage using the

Azure CLI, use –sku Standard_LRS.