Tag: failover

failover – Load Balance Multiple ISP connection

I am planning to setup a home network with multiple GBPS connections. Currently have 2x GBPS connections which have their own independent router and network. What I am planning to do is buying a ‘Mikrotik hEX’ which can provide Load Balancing/Failover for the two connections.

The current setup looks as follows:

https://i.stack.imgur.com/3FnYU.png

Also to eliminate the PON devices, will use a single switch with SFP ports. Switch VLANs will bridge ISP connection to the Routers WAN interfaces. The WAN connections will be load balanced and exposed as a single connection on to the LAN interface, which will be connected to another VLAN on the switch. As shown in the diagram below.

https://i.stack.imgur.com/3FnYU.png

Note: The diagram shows 4 WANs which I am planning for future upgrade once the need arises. For that I will be buying a more capable router with enough horse power. For now I will be sticking with 2 connections.

I have two questions:

  1. Is the plan going to work in the first place? I have only done setup for basic home networks before this. I have come up with this design after a lot of reading but that is it. I have zero practical experience with more complex networks.
  2. Will Mikrotik hEX and Mikrotik CRS112-8G-4S-IN suffice for this? I know I will be limited by line speed of 1Gbps, which should be fine. I am mainly looking Auto Failover/Load Balancing to reduce network downtime with close to 1 Gbps links on LANs.

Any other inputs to improve upon this are welcome.

availability groups – The Windows Server Failover Clustering (WSFC) resource control API returned error code 19

Here are the details of that error code (19):

ERROR_WRITE_PROTECT

19 (0x13)

The media is write protected.

You need to consult the cluster log (use Get-ClusterLog to get that) for additional details about what writes failed within the cluster operation being performed. Check that out and update your question with any errors you see.

That being said, combined with this symptom:

…if you reboot second node, database wont up.

You might be experiencing disk problems. Check the Windows system event log and SQL Server error log for messages related to failed writes or corruption.

Database Failover not happening for Sharepoint 2016

I have a Sharepoint 2016 farm with shared roles in the following configuration.

  • 2 X Web Front End Servers with Distributed Cache
  • 2 X Application Servers with Search
  • 1 X Domain Controller
  • 2 X SQL Servers in Failover Cluster (configured with High
    Availability)

However when I do a Manual failover from DB-Server-1 to DB-Server-2 , the failover happens successfully but I get the following errors.

“Cannot update database on SQL Server instance ‘SQL-LISTENER-01’. Database is read/only. Additional error information from SQL Server is included below.
Failed to update database “SharePoint_Config” because the database is read-only.“

“SQL database login for ‘SharePoint_Config’ on instance ‘SQL-LISTENER-01’ failed. Additional error information from SQL Server is included below.
Login failed for user ‘TEST-DOMAINSPFarm’.“

Shutting down the DB-Server-2 has no effect and the sharepoint farm works fine. But setting DB-Server-1 as secondary and DB-Server-2 as primary causes the sharepoint farm to go down.

Sync MySql Replication from Master2 to Master1 after failover

Due to Disk space issue Master2 server crashed and it was rebuilt again using mysqldump of Master1.
Both Master 1 and Master2 are in sync and Master2 is in Read_only mode.
During the crash, I stopped the Slave instance in Master1 and it’s been over a week now. Now how to restart replication from Master2 to Master1.
Can changing the Master Log position in Master1 to current Master2 status works?

DNS Made Easy’s failover service vs Cloudflare

Anyone have any experiences good or bad with with DNS Made Easy’s failover service?… | Read the rest of https://www.webhostingtalk.com/showthread.php?t=1837073&goto=newpost

Failover in MySQL Chain Replication

We have a 4 server setup, 1 master, 3 daisy-chained slaves, in the following setup:

A (master) -> B (slave) -> C (slave) -> D (slave)

(the servers B and C and D are running with log-slave-updates)

In normal operation everything works as expected: if we add new data to A, we see it show up quickly in B and C and D

Now we want to create a failure scenario — we shutdown A and want to make B the new master:

B (master) -> C (slave) -> D (slave)

It seems like what we want to do is fairly simple — switch B from Slave to Master

We are trying to follow the documentation “Switching Sources During Failover”
https://dev.mysql.com/doc/refman/8.0/en/replication-solutions-switch.html

The doc says ” On the replica Replica 1 being promoted to become the source, issue STOP REPLICA | SLAVE and RESET MASTER.”

So if we’re reading correctly, to switch B from Slave to Master all we have to do is run:

STOP SLAVE
RESET MASTER

Running “STOP SLAVE” causes no issues, but running “RESET MASTER” breaks the replication to downstream staves C and D. This is the error on C:

Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Client requested master to start replication from position > file size'

So what is the point of “RESET MASTER” and why does it break the chain? Is there any harm in omitting it/how does one properly do a failover in MySQL chain replication?

clustering – SQL Failover Cluster

First sorry for my English, I am French speaking 🙂

I’ve searched and did not found any information on how to do this.

Let me explain (see file attached)

I know how to setup an SQL failover cluster, did it and it works perfectly.

Here is my situation : Node1 and Storage A is in one location (city) and Node 2 and Storage B is in a second location (different city).

Node 1 and Node 2 are connected to Storage A and Failover works perfectly.

NOW here is the catch.

How to setup so that if Storage A fails and I want to failover to Storage B.

I am wandering if its even possible since I have not found a single example on the net.

Thanks you all.

SQL Failover Cluster

Steps to apply windows updates to sql failover cluster?

What are the steps to apply windows updates to a active/passive two node sql failover cluster? My initial thought was to apply windows updates to passive node/reboot and then failover and repeat process but not sure. Do I need to stop the db’s and sql agent jobs before failover?

sql2014
windows 2012r2

linux – implementing a failover service for containers

Two VMs are hosted on the same machine, let’s name them VM1 and VM2. Both VMs are hosting a runC container running a server application, a client is running directly on the host machine and is connected to service running in the container in VM1.

I want to build a failover service where if I close the container on VM1, the client should get connected to the container running on VM2.

I’ve implemented and tested a floating IP using keepalived and VRRP as suggested in this link, but this works only when the whole VM fails, I have to implement fault tolerance service for a container if the container on VM1 fails, the client should get connected to a replica running on VM2 even if the VM1 is up i.e the container fails but the VM hosting that container is up.

The restriction here is I do not want to use any Load Balancer/HAproxy service which can become a single point of failure.

behavior of a Sql Server availability group listener and a jdbc client during a failover?

i have a question about the behavior of the AG listener during a failover… when the failover happens, I realize that all the connections on both primary and secondaries are closed.

if the client apps are using one of the blessed client libraries (such as microsoft jdbc > 6.0) they will then start immediately trying to reconnect to the ip addresses associated with the listener. But what happens during the 10 second period (or whatever it is) for the failover to complete? Might a client successfully get a connection, only to get a fatal error message when it tries to use it? Or is something done to ensure that no client will get a connection successfully during failover itself, so that that when a client does successfully get a connection, it is actually usable?

(Also, specifically for a java client using a recent microsoft jdbc driver, does it try only once per getConnection() call? Or will it keep polling until a logintimeout is hit?)

I realize i’m mixing questions about server behavior with client library behavior but I’m trying to understand the whole scenario; thanks.