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Questions tagged [high-availability]

High availability is an architectural consideration often involving degrees of redundancy to insure availability in case of system or component failure.

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High Availability with the Supermicro SMC2208 (MegaRAID)

I haven't been able to find a solid answer in the documentation, nor from the vendor since this model is out of production. We have a Supermicro SMC2208 24-drive-bay RAID. I would like to create a ...
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1answer
31 views

Handling traffic spikes for a medium scale ecommerce application

Let me first briefly describe our stack. Single EC2 instance with 4 vCPU and 16 GB RAM running Ubuntu [m4.xlarge] Single RDS instance with 2 vCPU and 8 GB RAM running MySQL 8 [db.m5.large] We are ...
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Serverless DDNS in an “AWS Like” cloud?

I am on a closed network, usin a derivative of AWS. I have one VPC in 2 Availability Zones, with a small range of IPs. Many of my VMs have dynamically assigned IPs. Right now, my Puppet Master is in ...
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1answer
12 views

Redis sentinel: force switch to another master

Context: I have 3 redis nodes, and 3 sentinels. The failover works properly. When I'm taking the master down, another master is elected. Need: I need a way to test the behavior, to make sure ...
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6 views

How does redis sentinel know about a new master when it was down during the switch?

I have three redis nodes, and I need to deploy three sentinels. Considering my redis nodes r0, r1 and r2 are online. r0 is currently the master. All three sentinels are initially started with a ...
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10 views

Recommended ratio of Redis masters to slaves

When using Redis clustering, is there a recommended ratio of Redis masters to slaves? Is it recommended to have four masters with one slave each, or two masters with three slaves each? I'm uncertain ...
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22 views

glusterfs for wordpress hosting

I've seen many tutorials recommending glusterfs for distributed web application hosting. Is this really the best practice for small scale load balancing? It seems the latency issue is slowing us ...
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1answer
19 views

Best approach to tier 2 PKI with multiple subordinates with ADCS

I'm looking for some guidelines toward the best approach to setting up a Tier 2 PKI with ADCS that has 2 subordinate CA's for high availability. I have the following questions regarding this: Is ...
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1answer
31 views

Can't authenticate to cassendra: cannot achieve consistency level LOCAL_ONE

Context: We have a Cassandra cluster with 3 nodes deployed as a Stateful Set in Openshift. The three nodes are configured in the same datacenter, same rack. I also made a script to test the ...
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2answers
28 views

High Available service - IP/DNS single point of failure

I'm looking for High Available solution for websites and already find Kubernates , Docker Swarm ... but all these things should balance only webserver , db and other running service in the cluster. ...
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33 views

High availability website using IIS / windows server

My website is currently running on a single windows server 2016 machine with IIS and SQL server 2017. Every time there's a windows update, new hardware install, etc., my site goes offline. My goal is ...
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10 views

Proxmox HE shared storage redundancy

I am currently reading myself into Proxmox HE clusters. They mention everywhere how important it is to have redundant components (NICs, switches, etc.) but it is never mentioned that the ISCSI target ...
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17 views

SystemArch: How to proxy multiple physical mailservers behind one DNS?

Assuming following system architecture: internet | smtp.mydomain.com (TLS/SSL enabled SMTP-proxy?) | +--------DMZ----...----+ | | ... | ...
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1answer
30 views

No traffic arrives via openstack floating IP and pacemaker/corosync

I am following the steps from https://fuga.cloud/academy/tutorials/ha-vip-with-corosync-on-openstack/. I am missing a reason why traffic going into the external floating IP is not arriving correctly ...
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29 views

Running HA Consul in two datacenters

One of my clients would like to run consul in two datacenters. Both datacenters Berlin and Frankfurt should result in a High Availability setup, where one datacenter can be taken offline or die ...
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87 views

Failover Nginx reverse proxy

I am looking to setup my Nginx reverse proxy to handle a server failure or Nginx failing for some reason or another. I know how to configure nginx to work as a load balancer/ reverse proxy for other ...
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2answers
244 views

How to get DRBD to automatically start after reboot, mount volume, start service, and configure primary/secondary

I have a great working version of DRBD across two Debian Stretch servers which I created by following this awesome guide: https://www.howtoforge.com/setting-up-network-raid1-with-drbd-on-debian-...
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23 views

Multiple apache reverse proxies behind 1 external IP

I have honestly tried searching on this topic, but I keep landing on articles explaining how to load balance web servers behind proxies, which is not what I want to do. My setup is like this: WWW -...
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1answer
65 views

Creating a VSAN datastore

I am trying to set up my first HA cluster and I have some hard time digging into VSAN datastores. I have two ESXi hosts both with two 480 SSD hard drives in RAID 1 Can I add the existing hosts' ...
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46 views

Is it possible to migrate bare-metal ovirt host+engine to self-hosted without full cluster rebuild?

I have ovirt cluster of 2 CentOS hosts. Host1: host for regular VMs + bare-metal ovirt-engine Host2: host for regular VMs They have shared NFS storage. Is it possible to migrate to self-hosted system ...
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0answers
12 views

Create a reliable architecture to avoid downtime

Today I have several droplets (VPS) on DigitalOcean for single tasks, one VPS for each task: Apache / PHP PostgreSQL NodeJS ElasticSearch Exim Unfortunately these days one of these droplets went ...
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1answer
40 views

Advice for high availability

Talking about high availability im in search of advice for my particular situation. We have configured a blade center from ibm our active directory server using vmware (windows server 2008 r2), and ...
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1answer
224 views

Redis: read-only slave vs fail-over slave?

I'm reading a lot of documentation around Redis network configurations, and I'm confused about how it seems the requirements in the architecture mental model I had, don't seem to map with the current ...
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1answer
54 views

MongoDB/ElasticSearch in Kubernetes

I am exploring the Kubernetes toolset and have now my dedicated 3 nodes cluster up and running. Next steps are migrating our company projects to the cluster. As we use MongoDB and ElasticSearch and ...
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0answers
50 views

nginx upstream configuration to switch back and forth between two servers

I've got a legacy web application, it sometimes crashes. Also, it have an application cache residing in the virtual space of the app itself - it can not share the cache data with other instances of ...
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2answers
154 views

How can I configure haproxy to put two frontends to access owa online?

I am facing a problem with HAPROXY on an Ubuntu 16.04 server when redirecting to show OWA on the internet. I have a domain, and I installed exchange server 2013 on windows server 2012 r2. I need to ...
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0answers
26 views

Glusterfs dont mirror supposed mirrored folder

Gluster dont replicate mirrored content: xfce4-terminal -T LocalTerm exit At LocalTerm: PS1='[\u@\h]-[\D{%T}]-[\W] => ' lxc profile copy default default-bkp lxc profile set default raw....
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0answers
68 views

VMWare Fault Tolerance vLockStep

I would like to understand how vLockStep is working and could only find very high level description. The current documentation say that disk read but not disk write performed by the primary are ...
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5answers
383 views

KVM+DRBD replicated between two active-passive servers with manual switching

I need to build 2-node cluster(-like?) solution in active-passive mode, that is, one server is active while the other is passive (standby) that continuously gets the data replicated from active. KVM-...
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0answers
24 views

Recovering VCS 2 node cluster in DR?

We are looking for a solution to recover the 2 node VCS Cluster at DR location for a DR Test. Prod: Hardware is Dell with 24 cores 64 GB RAM with Suse 11.4 Linux over SAN Boot & 4 NIC's of 1 Gig. ...
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1answer
40 views

Debian HA cluster with 3 servers, run script on outage for DNS failover

I am currently building a HA cluster, the database is already on Galera, the last thing would be, trigger an DNS update to redirect the traffic to another machine. Is there any software, which can ...
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1answer
171 views

HA Squid with Keepalived

We're trying to setup two HA services: Explicit forwarding proxy using Squid (port 8080) SMTP relay to Office365 using Postfix For both setups we have 2 VM's with a default Debian 7 install, and I'...
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1answer
28 views

IP Failover using Route53

I have 2 Nginx Load balancers, running on AWS, each with an elastic IP address. I want to implement fail-over on them. Can I use Route53 to setup health check, so whenever one server goes down, then ...
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1answer
41 views

Windows server fail over clustering between two seperated server [closed]

i have two windows server with speared location,hard and SQL server. how i configure failover between them (IIS and SQL Server)? is there any scenario for this ? is it better to use shared storage ? ...
2
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1answer
43 views

Implementing a Highly Available backend gateway for a cloud app on AWS

I have 2 EIPs allocated for a cloud app, which are used in round robin DNS. I'd like to have some sort of high availability mode for our 2 gateways (proxies) which are associated with those EIPs, so I ...
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0answers
286 views

DLM and CLVMD not starting on pacemaker redhat HA

I was trying to configure an active-active cluster w/ gfs2, I followed the following instructions: pcs property set no-quorum-policy=freeze pcs resource create dlm ocf:pacemaker:controld op monitor ...
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1answer
76 views

High availability mirroring without separate partitions or LVM on Ubuntu 14.04 LTS

I'm on AWS with my clients for a long time now but I'm going to need cut costs now to keep providing my services. On AWS I'm using RSync to keep some folders synchronized and DRDB to provide high ...
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1answer
113 views

Is keepalived + VIP needed for DNS?

I have two dns servers running powerdns, they are using native replication, ie, they are hitting an HA postgres cluster. When creating a new server, I specify the IPs of the two DNS servers in dns-...
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2answers
200 views

nginx reverse proxy for high availability setup?

The scenario is like this, I have a nginx reverse proxy server in front of two app servers which are backups of each other, I want nginx to forward all user requests to the first app server at first, ...
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3answers
112 views

Azure high availability solution with synchronization of website and SQL server data

We have a web solution that we sell and it comes with 1 dedicated Azure VM containing everything it requires to run the application: ASP.NET web application Production environment QA environment SQL ...
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1answer
26 views

windows 2016 failover cluster

Windows 2016 Failover Cluster with two nodes, both nodes have subnet A and B physical interfaces, and a generic service defined with client access point on both subnet A and B. Can I fail over from ...
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1answer
237 views

Configuring Heartbeat to run shell script

I set up a high availability system with Heartbeat, I wish that when there was a drop in the main cluster and the secondary cluster was activated, Heartbeat start in it and execute a shell script. ...
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0answers
38 views

MongoDB replica set not picking a PRIMARY with 4 of 6 members UP

I have 6 instances running on Scaleway , 3 on ARM servers and 3 on Virtual Ubuntu Servers . mongodb1 ARM (mongodb 3.4.9) mongodb2 ARM (mongodb 3.4.9) mongodb3 ARM (mongodb 3.4.9) mongodb4 VPS (...
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0answers
17 views

WordPress High Availability Setup - Feedback needed [duplicate]

So I got the lucky job to setup a High Availability WordPress Setup to serve around 100k views per Day. I started to create a server diagram and would like to hear your feedback for improvements. ...
2
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1answer
756 views

bond slave interfaces not getting the same aggregator id on LACP

I have a bug on some servers where LACP (802.3ad) is not working. I have on all servers a bonding device bond0 with two eth slaves and each interface is plugged on a different swich, and both switches ...
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0answers
291 views

How to set up tcp check with keepalived?

Trying to set up HA bastion servers. Failover, load balancing is not needed. Two servers running debian. bastion01 and bastion02. 192.168.0.10 and 192.168.0.11. Floating IP is 192.168.0.12. I started ...
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0answers
80 views

Zabbix agent multipath?

I have some VMs where Zabbix agents are used to gather metrics. Since these VMs are on several different physical hosts it would only be very natural to run a Zabbix proxy on each of these hosts and ...
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3answers
385 views

Informix HDR failover doesn't work when primary DB server and Connection Manager/ICM are terminated simultaneously then ICM is brought back online

Automatic switchover is configured in a primary/secondary HDR server setup. The HDR cluster would be connected and replication is on. If the service is stopped gracefully on the primary server (NODE-...
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2answers
74 views

Site-aware cluster migrates VMs to random nodes, not to the preffered site

We have 2 physical host, 4 virtual-node (HyperV Server VMs, 2 on each host) cluster which is running some nested test VMs (using mentioned HyperV Server). In short it is ment as a lab environment ...
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2answers
84 views

DB2 10.5 HADR read only standby applications don't reconnect to primary

Scenario: server SERV_A, database DBNAME primary server SERV_B, database DBNAME standby with DB2_HADR_ROS enabled Then this situation occurs: connection CON is made from client to DBNAME when ...