Questions tagged [high-availability]
High-availability technologies mask the effects of hardware or software failure, so that perceived downtime for users and applications is minimized.
468 questions
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After recovering from session timeout expiry, at what point does the primary start waiting on synchronous replicas to harden?
The documentation tells us what happens when session timeout for a synchronous Availability Group replica expires
"Even if a disconnected replica is configured for synchronous-commit mode, ...
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Should I Switch from Master–Slave to Master–Master Database Replication in VoIP Environments?
I have two Asterisk+FreePBX servers that share a common database. The services are active on one server at a time, and in the event of a failure of the main server, the services are then started on ...
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After a failover to a DR region, the becomes "reverting/in Recovery" in the primary node
we have a 10+TB database. Whenever we failover it, the databases becomes with a session running a null command, with a HADR_DB_COMMAND wait_type.
I believe this is related to a rollback or something? ...
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Is this Patroni topology safe?
My organization is planning to implement a high-availability PostgreSQL cluster using Patroni and etcd. However, we only have two data center sites available, which makes deploying a standard 3-node ...
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Cloudstack HA MySQL replication
I'm in the process of setting up a Cloudstack cluster with HA and I need suggestions.
My current setup is a two node cluster. Each node runs the cloud stack management and a MySQL instance. I created ...
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Migrate availability group listener to a different availability group
Hopefully a simple question to answer!
Can you point an existing availability group listener to a different availability group?
Current production environments are using Enterprise licenses and the ...
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DB in a always on availability group on secondary node is unsynchronized / suspect after drive filling up
One of the drives filled up on our servers causing the backups to fail. Stupid, I know.
Now I'm seeing our main DB is not syncing / Suspect. I did run
DBCC CHECKDB ([mainDB]) WITH NO_INFOMSGS, ...
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Multi subnet failover for Azure PaaS failover groups
should the multisubnetfailover=True parameter be added to connection strings to Azure failover groups?
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Is it possible to use Postgresql two-phase-commit without downtime?
Suppose that I have some application servers writing to two databases using two-phase-commits to keep the data consistent. As long as both databases are up everything is fine.
But now one database ...
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PostgreSQL HA Cluster equivalent to SQL Server Availability Group Listener object
I've setup a PostgreSQL v16.6 HA Cluster using repmgr. Ensured replication is working between primary and standby nodes. Then I tried simulating a failover event by shutting down PostgreSQL service at ...
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Why do NoSQL databases tend to favor availabilty instead of consistency?
From my current limited understanding of NoSQL databases, it seems like there are two basic elements.
First, how they store data compared to SQL databases. NoSQL databases store a blob of data, ...
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etcd is out of space, getting NOSPACE alarm
We have two node patroni postgres databases on preprod environment. Today I tried to do patronictl edit-config and saw etcd was out of space. I looked at /var/lib/etcd/member directory and it was ...
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Redis server error: "Cannot assign requested address" under high traffic from Nginx to PHP to Redis
I'm experiencing an issue with my Redis server where I get the following error under high traffic:
Cannot assign requested address
my php code:
<?php
$redis = new Redis();
try{
$redisConnected ...
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Logon Trigger On HA
Here is the setup: on MSSQL-Server-2022, we have a contained availability group with 4 replicas: 3 synchronous, 1 asynchronous, and a listener.
We created a logon trigger to limit access to a specific ...
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Can I use MSSQL's Failover Partner parameter without configuring database mirroring?
I have 2 MSSQL databases that are not part of the same cluster but they are synchronized manually (without database mirroring configured)
I want my client applications to try connecting to the first ...
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