There is little documentation on how ASTRA DB stores data. So, i could not do much research on this. I wanted to know which of the storage options do ASTRA DB use to store data in azure blob. The storage options are
LRS(Locally Redundant Storage) - copies data synchronously three times within a single physical location in the primary region
ZRS(Zone-redundancy storage) - Copies data synchronously across three Azure availability zones in the primary region
GRS(Geo-redundant storage) - Intermediate option with failover capabilities in a secondary region
GZRS(Geo-zone-redundant storage) - Optimal data protection that includes both GRS and ZRS.
Thanks
Serverless databases are automatically replicated across three availability zones - see About your Astra DB database.
Each Astra DB database uses replication across three availability
zones within the launched region to promote uptime and ensure data
integrity.
This would mean ZRS in the case of Azure.
Related
Cosmos DB documentation (https://learn.microsoft.com/en-us/azure/cosmos-db/high-availability#what-to-expect-during-a-cosmos-db-region-outage) says that "Given the internal Azure Cosmos DB architecture, using multiple write regions doesn't guarantee write availability during a region outage. The best configuration to achieve high availability during a region outage is single write region with service-managed failover."
Does that mean multi-region writes is just for distributing workloads with limited availability? What is the internal Azure Cosmos DB architecture and where can I get it?
In my understanding, if there is an outage in one region, all writes from that region should be re-directed to other region writes and seamlessly update the database. Is it correct?
I have an Azure Storage account with 2TB of data. For the design of a disaster recovery solution how I can recover it on a remote site with huge data?
Azure Storage has different data redundancy modes to provide recovery in case of a disaster.
Locally redundant storage (LRS) copies your data synchronously three
times within a single physical location in the primary region. LRS is
the least expensive replication option, but is not recommended for
applications requiring high availability or durability.
Zone-redundant storage (ZRS) copies your data synchronously across
three Azure availability zones in the primary region. For applications
requiring high availability, Microsoft recommends using ZRS in the
primary region, and also replicating to a secondary region.
Geo-redundant storage (GRS) copies your data synchronously three times
within a single physical location in the primary region using LRS. It
then copies your data asynchronously to a single physical location in
the secondary region. Within the secondary region, your data is copied
synchronously three times using LRS.
Geo-zone-redundant storage (GZRS) copies your data synchronously
across three Azure availability zones in the primary region using ZRS.
It then copies your data asynchronously to a single physical location
in the secondary region. Within the secondary region, your data is
copied synchronously three times using LRS.
Why do we need Azure backup for our VMs (disks) on azure, when azure storage account provides different replication options like LRS, ZRS, GRS, RA-GRS.
All the data is already replicate in different region (in case of GRS), what advantes I will get out of Azure Backup.
All the data is already replicate in different region (in case of
GRS), what advantes I will get out of Azure Backup.
Replication is not backup!
It is true that when you opt for GRS replication, 6 copies of your data is maintained (3 in primary and 3 in secondary) but when you delete the data from primary, data from secondary is automatically deleted.
UPDATE
You mean, if any data is deleted/corrupted due to some error/bug, can
be reproduced from backup and it is not possible in case of storage
replication.
You're absolutely correct!
But Microsoft sells "Azure backup and Site recovery" as a BCDR
strategy. In context of any disaster, why not just rely on Storage
replication. Any advantages of Azure backup/site recovery?
I have not used Azure backup so let me answer it from Storage Replication point of view. To put things simply, "In context of Azure, a disaster is not a disaster unless Microsoft thinks it is a disaster". Till the time that happens, you don't get access to secondary assuming you have opted for GRS replication (with RA-GRS, you obviously have an option to read the data from secondary at all times).
Furthermore if you choose LRS or Premium LRS replication and there's indeed a disaster in one data center, all of your data will be lost. With Azure Backup, you at least have a copy of your data lying somewhere safe and you could recreate your environment based on that backup.
I know this question is old but MS provide a solution for Disaster recovery by Storage account
We may have 2 solution for dealing with Disaster
https://learn.microsoft.com/en-us/azure/storage/common/storage-disaster-recovery-guidance?toc=/azure/storage/blobs/toc.json
it said :
If the primary endpoint becomes unavailable for any reason, the client is no longer able to write to the storage account. The following image shows the scenario where the primary has become unavailable, but no recovery has happened yet:
enter image description here
The customer initiates the account failover to the secondary endpoint. The failover process updates the DNS entry provided by Azure Storage so that the secondary endpoint becomes the new primary endpoint for your storage account, as shown in the following image:
enter image description here
Is there any way to migrate Azure SQL server/database from one geographical region to another region? Thanks.
You can use Geo-replication to create a replica of your actual databases on the new desired region, then you can failover all of them making databases on the new region the primary databases, now you can drop all secondary databases on the old original region. You can learn about setting up Geo-replication using Azure portal here.
Another option is to copy the databases to a server located on the desired region using the Copy Database feature as explained here.
A third option is exporting the database to a blob storage as bacpac then import it to a SQL Azure server on the new region as explained here.
Finally, you can also use SQL Data Sync (as explained here) to copy databases to the new region on a new server, and keep the servers synchronized, then you can remove databases from the sync groups, remove SQL Data Sync and drop the original databases.
Hope this helps.
The official Azure documentation about moving SQL resources across regions.
I want to confirm our understanding of how our Azure SQL databases are being backed up to enable point in time restore. We have not currently configured geo-replication to have the database available in another region. We may in the future as some data analysis is done. But my understanding is that the database is still being backed up to a geo redundant location so I could do a geo-restore if there was an issue with the data center that houses my sql database. Is that correct or do I need to enable geo-replication and pay for a second database in order to have a disaster recover option if the datacenter had an issue.
To clarify further: I think this article states what I'm saying in the Geo-Restore section.
https://azure.microsoft.com/en-us/documentation/articles/sql-database-business-continuity/
Thanks
Yes, all databases have a geo-replicated copy for disaster recovery purposes. For more details, please see the following: https://azure.microsoft.com/en-us/blog/azure-sql-database-geo-restore/
Geo-restore uses the same technology as point in time restore with one
important difference. It restores the database from a copy of the most
recent daily backup in geo-replicated blob storage (RA-GRS). For each
active database, the service maintains a backup chain that includes a
weekly full backup, multiple daily differential backups, and
transaction logs saved every 5 minutes. These blobs are geo-replicated
this guarantees that daily backups are available even after a massive
failure in the primary region.
Yes, Azure SQL Databases are automatically backed up to a different Azure data center using Geo-Replication. This is an automatic features of Azure SQL that is baked into the service offering.
Here's a blog post with further information about Azure SQL Data Replication:
https://azure.microsoft.com/en-us/blog/azure-sql-database-standard-geo-replication/