brandon/oam
1
0
Fork 0
mirror of https://gitea.com/mcereda/oam.git synced 2026-02-09 05:44:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

fix(kb/aws/rds): confirm no (perceived) downtime for storage type and multi-az conversions

Browse Source
This commit is contained in:
Michele Cereda
2025-09-29 12:53:13 +02:00
parent 7bf0325b92
commit e1295c09bb
1 changed files with 19 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
knowledge base/cloud computing/aws/rds.md
View File

@@ -214,9 +214,9 @@ Use one of the following methods:
[DMS][what is aws database migration service?]<br/>
This **should** require **minimal** downtime.
RDS instances using GP2 storage can convert their volumes to GP3.<br/>
There seems to be no downtime associated with this operation, but performances **will** be impacted until the process
ends and the change will trigger [storage optimization].<br/>
RDS instances using GP2 storage can convert their volumes to GP3 just by modifying the DB instance.<br/>
This operation does cause downtime, but performances **will** be impacted until the process ends and the change **will**
trigger [storage optimization] for the instance.<br/>
Refer [Changing RDS storage from gp2 to gp3].
### Storage optimization
@@ -547,20 +547,6 @@ system maintenance, and helps protect the database against DB instance failure a
> One **cannot** use the standby replica to serve read traffic.<br/>
> To serve read-only traffic, use a Multi-AZ DB cluster or a read replica instance instead.
One can convert existing Single-AZ DB instances to Multi-AZ deployments just by modifying the DB instance.<br/>
This process involves minimal to no downtime, and requires planning around storage and performance impacts.
During a Single-AZ to Multi-AZ conversion, RDS:
1. Takes a snapshot of the primary DB instance's EBS volumes.
1. Creates new volumes for the standby replica from that snapshot.
1. Turns on synchronous block-level replication between the volumes of the primary and standby replicas.
It seems one can convert existing Multi-AZ DB instances to Single-AZ deployments just by modifying the DB instance.<br/>
This process seems to involve minimal to no downtime, and requires planning around storage and performance impacts.
During a Multi-AZ to Single-AZ conversion, RDS typically keeps the instance in the AZ where the primary was located.
Multi-AZ DB instance deployments have increased costs, and write and commit latency compared to Single-AZ deployments
due to the synchronous data replication to the standby replica.
@@ -571,6 +557,22 @@ the primary DB instance became unavailable. Large transactions or a lengthy reco
time.<br/>
When the failover is complete, it can take additional time for the RDS console to reflect the new AZ.
One can convert existing Single-AZ DB instances to Multi-AZ deployments just by modifying the DB instance.<br/>
This process involves minimal to no downtime, but requires planning around storage and performance impacts if done on
active instances.
During a Single-AZ to Multi-AZ conversion, RDS:
1. Takes a snapshot of the primary DB instance's EBS volumes.
1. Creates new volumes for the standby replica from that snapshot.
1. Turns on synchronous block-level replication between the volumes of the primary and standby replicas.
One can convert existing Multi-AZ DB instances to Single-AZ deployments just by modifying the DB instance.<br/>
This process involves minimal to no downtime, but requires planning around storage and performance impacts if done on
active instances.
During a Multi-AZ to Single-AZ conversion, RDS typically keeps the instance in the AZ where the primary was located.
## Operations
### PostgreSQL: reduce allocated storage by migrating using transportable databases