Questions tagged [fault-tolerance]
The fault-tolerance tag has no usage guidance.
89
questions
4
votes
1
answer
370
views
How can i get a virtual machine in Hyper-V to carry on running in failover cluster. 2 Nodes, Server 2019
Forgive me if I am missing something obvious but I am very new to servers and failover clustering. I haven't found a question that quite answers what I am looking for yet.
My goal is to make a VM run ...
- 41
16
votes
1
answer
3k
views
What's the difference between a "degraded" RAID 6 array and a "clean" RAID 5 array?
Suppose you have two RAID arrays, one with N disks and one with N+1 disks. The array with N disks was formatted as a RAID 5 and left alone, while the other array was formatted as a RAID 6 before one ...
- 306
1
vote
0
answers
140
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Computing stripe count for erasure coded storage
I'm setting up a ceph cluster (first time for me) which in the end will be made of ~100 disks spread over 10 hosts. I'm going with a single erasure coded data pool to maximize disk space; my ...
- 281
0
votes
2
answers
145
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Can I setup DNS in such a way that if one IP address fails, it uses the other IP?
I intend to create a SaaS with two Load Balancers. If one load balancer goes down, 'MySaaSApp.com' will point to the other load balancer. Can such be accomplished through DNS Records alone? Thanks!
- 1,345
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standalone mysql 5.7 instance on a preemptible node, which settings can make it run in the most fault tolerant way possible?
Simplifying, I have a standalone mysql instance running on a docker container hosted on a preemptible node.
That means that at least ever 24 hours, the underlying node is killed, and a clean shutdown ...
- 11
0
votes
1
answer
526
views
How to choose right AWS EC2 instance for serving MySQL
Recently we have noticed that our application has some errors related to the MySQL load.
There are some basic queries on large database (approximately 32 GB) which takes longer time than expected.
For ...
- 101
0
votes
1
answer
765
views
Print Server Redundancy in VMware ESXi
I'm having a challenge figuring out the best way to get the highest possible uptime on my 2 print servers.
The best solution would be if one of the servers function as my primary print server, and the ...
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1
vote
1
answer
777
views
Vmware Esxi Vcenter 6.7 Fault tolerance for VM is greyed out
I'm very new to VMWARE. I'm trying to do fault tolerance for one of my VMS on Vcenter 6.7 but the Fault tolerance tab is greyed out for some reason. I have to 2 esxi servers in my vcenter and both are ...
- 11
0
votes
1
answer
215
views
Optimal (fault-tolerant, low-cost) way to keep a Write-Ahead Log (WAL) in IaaS?
I am working on a greenfield project for a “cloud-native” DBMS, with “cloud-native” meaning that the guarantees (e.g. ACID) it makes will depend on the presence of certain backing IaaS services (e.g. ...
google-cloud-platform
2
votes
2
answers
273
views
ESXi Fault Tolerance Network Issue - FT traffic flooded?
I've setup a 2-nodes vSphere cluster. Each node is equipped with 4x1GE NICs. I have set a single vSwitch in each node, using all 4 vmnics as adapters and the following ports:
Management: vmKernel ...
- 154
0
votes
1
answer
260
views
Network fault tolerance for LAN clients
Goal: Provide fault tolerance for LAN clients so access to a service with a service-level agreement (SLA) is not interrupted in the event of an incident with a physical switch.
Question: Is there a ...
- 18
1
vote
0
answers
109
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 ...
- 11
1
vote
2
answers
1k
views
What is the recommended way to setup Docker on a multi-drive server in a fault tolerant mode?
I have a server with 4 250GB sata drives on regular sata controllers. I would like to setup Docker on some sort of fault tolerant file system so that if one of the drives fails the whole thing doesn't ...
- 605
0
votes
1
answer
237
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Is Setting up backup DNS only for A Record possible?
So we Have a server on AWS for our website and we use another provider for our e-mails.
We have a backup policy in place where we have at least 3 places with all the data from our main server one of ...
- 173
0
votes
2
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188
views
Concrete difference between faults and attacks [closed]
I don't know if it is the good place to ask this question but I believe it is OK. My question is simple: how can one make a difference between a fault and between an attack? A denial of service could ...
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3
votes
1
answer
507
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vsphere network design for vsan and ft-enabled cluster
I am looking for some recommendations on the network design for my ha-ft and all-flash-vsan-enabled vsphere cluster.
I've planed around vsphere a bit, but newbie to vsan and ha/ft. I've Googled and ...
- 223
1
vote
1
answer
2k
views
How to restart a systemd service when a file has not been modified for a period of time?
My setup has a systemd service that should periodically write to a file. I would like to monitor the file for changes, so when it hasn't been modified for a while, I know the service has bugged out. I ...
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1
vote
2
answers
181
views
Backup strategy for dedicated LEMP stack server
We currently have an application running on a dedicated server which utilizes a LEMP (Linux, Nginx, MariaDB, PHP) stack. Right now we are only doing backups at a set interval (every x hours). I have ...
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-2
votes
1
answer
84
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How to create a group of servers listening on the same IP-address, allowing failover/takeover? [closed]
I'd like to deploy a web application in a robust manner.
The application itself is written using Elixir, which runs on top of Erlang/OTP, meaning that the application can be deployed on different ...
- 149
1
vote
1
answer
4k
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HAProxy - clear stick-table from the command line
I'm using HAProxy to do automatic failover for an LDAP server, but I don't want automatic fail-back.
The scenario is that I have 2 nodes, s1 and s2. I want all traffic going to s1 unless it fails, ...
- 207
2
votes
1
answer
3k
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Failover setup of virtual machines using KVM
I have two physical servers each having: 2 CPUs (6 cores each), 4 network interfaces, 128GB RAM, 4 x 200GB SDD, 2 x 1TB SAS HDD and 1 configurable switch like Cisco Catalyst with support of vlans.
I ...
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7
votes
1
answer
200
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Storage Spaces Direct MTBF
I'm testing S2D now and I would like to calculate MTBF for the whole system. It seems very fragile to me:
Let's have 4 nodes (x) with 12 drives (y) in each. MTBF for one node is 1/12 of single drive ...
- 547
1
vote
1
answer
523
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Fault-tolerant S3 website hosting
Due to the recent S3 downtime episode on the East Coast, I want to ask the community what is the best way to implement a fault-tolerant S3 website hosting solution?
From my understanding, you need to ...
- 113
8
votes
3
answers
7k
views
Shared storage options for ESXi HA cluster
I am seeking recommendations for shared storage options to support ESXi HA cluster (note I'm NOT asking for product/brand/model recommendation - I know this is against the rules here). I am asking ...
- 223
1
vote
1
answer
964
views
rsyslog and elasticsearch: How to configure multiple servers?
We are currently setting some hosts to forward their logs via rsyslog and omelasticsearch to an elasticsearch cluster. The manual for omelasticsearch seems to allow only one server name of the ES ...
- 315
0
votes
1
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127
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Apache Mesos Master on every node
Is it good idea to launch mesos master and mesos slave together on every node?
If no, how to calc number of master nodes?
- 103
0
votes
1
answer
93
views
Azure Traffic Manager fault tolerance
I have just answered Do I need Azure Traffic Manager with Azure API Services? Over on SO
Part of my answer was understanding the failure of all aspects of a solution to which I realised I really don'...
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10
votes
1
answer
12k
views
Systemd does not restart service, although Restart=always
Here is my unit file of a systemd service:
[Unit]
Description=Tunnel For %i
After=network.target
[Service]
User=autossh
ExecStart=/usr/bin/autossh -M 0 -N -o "ExitOnForwardFailure yes" -o "...
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2
votes
2
answers
893
views
Fault Tolerance with Windows Server Failover Clusters?
I've attempted to read numerous articles online about this and believe I'm "seeing the light", but I'd like to have it confirmed.
Do Windows Server Failover Clusters offer a fault-tolerant feature ...
- 23
5
votes
1
answer
16k
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Does balance-alb and balance-tlb support fault-tolerance?
I've read bonding.txt file of kernel documentation, it's clear about load balance, but are balance-alb and balance-tlb really fault tolerant?
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3
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1k
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mdadm fault injection testing with bad blocks or other unrecoverable errors
I recently lost a drive in my RAID array (and got an email from the system warning me of this, which was awfully nice) and after some drive shuffling and swapping in a new drive I'm all safe and ...
- 149
4
votes
1
answer
1k
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Distributed mirrored filesystem under FreeBSD
Can someone share their experience in building a distributed mirrored filesystem between multiple FreeBSD machines? I. e. we have two (three, four...) servers and special partition "part1" mounted on ...
1
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0
answers
228
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Can I use a reverse-proxy on a hosting service to redirect connections to multiple IPs while taking care of maintaining sessions?
I have a situation where I am trying to host my own web server because I need some custom software, including telephony, WebRTC, node.js, etc. However, my net connection in the town and country where ...
- 381
1
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0
answers
54
views
VMware ESXi - what happens when unable to create a secondary instance of a VM for fault tolerance
Is anyone aware what would happen if VMware ESXi is unable to start back up a secondary instance of a VM configured for fault tolerance? Is there a fallback plan to try and get the VM up? Or is the VM ...
- 635
4
votes
1
answer
466
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VMware High Availability questions
I can't seem to find the answers to these questions within the vSphere 5 Documentation center, so please share if you are aware of any aspects of these questions.
What happens to the failed VM that ...
- 635
2
votes
1
answer
2k
views
Combine 2 logical raid 0 drives to 1 logical raid 1 drive
I have an HP Proliant server with an P410i embedded array controller.
The server was originally setup with 6 physical drives with the OS on 1 logical drive with a raid 0 and 5 physical drives setup ...
- 109
0
votes
1
answer
1k
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vSphere High Availability, Fault Tolerance and Snapshots
I've heard claims from a vSphere server administrator that VMs configured for high availability continue to transparently function even in the event of an ESXi host failure. He also claims VMs ...
- 103
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2
answers
259
views
Never miss a HTTP post [closed]
I have a webservice that have a couple of "machine" clients connected to it that does HTTP post with data once in a while. The nature of the service is that I cant allow the service to loose a single ...
- 111
1
vote
1
answer
1k
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PHP - Memcached - Libmemcached - Handle cache server outage
I am working on ensuring our app degrades gracefully in case of a complete cache outage, which is highly unlikely, as we have minimum of at least 3 cache nodes to add to the cache pool, by way of PHP'...
- 1,698
1
vote
0
answers
464
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What database am I seeding from in a stretched DAG?
I have a stretched DAG across 2 sites, with 4 copies. One of the remote copies failed, and I issued a re-seed operation with the remote&working copy as a source.
Knowing this, I tried to work ...
- 8,921
0
votes
2
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739
views
pfSense CARP - WAN failure on firewall
I have recently configured 2 firewalls (on 2 DELL PowerEdge R210II with ESXI 5.1) with pfSense. We have several LANs and 2 WANs. Everything is running fine but I have a strange behavior: I can access ...
- 385
-3
votes
1
answer
75
views
Is it possible to use planet scale load-balanced virtulisation? [closed]
there are more and more implementations of distributed-virtualisation. A common one is Microsoft SCVMM.
Currently, such things are kept inside LANs, and a san or fiber-channel system is used for ...
- 177
2
votes
3
answers
791
views
When to employ server failover in a virtual environment
This question kind of got me thinking about fault tolerance in DHCP, so I did a little digging in my current environment and discovered that we only have 1 DHCP server per major site in our company ...
- 890
10
votes
3
answers
13k
views
Is round-robin DNS a possible solution for high availability?
Let's say I have 2 IPs for a given domain (round-robin DNS).
If one the IPs becomes unresponsive, will clients try to connect to the other IP? or they will just fail to establish comunication with the ...
- 1,510
2
votes
2
answers
2k
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Detect HP ML370 G5 Bad disk in RAID0
I have one HP ML370 G5 server. Which has four 146GB SAS disks and two 300GB SAS disks that are configured as RAID 0.
I have encountered a problem with one of my disks. The windows server event viewer ...
- 277
0
votes
1
answer
1k
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VMware ESXi/vSphere Fault Tolerance vCPU Limit
So I am aware that VMs in FT mode are limited to a single vCPU. Is it possible to assign multiple cores to the single vCPU, and still have the VM support FT mode? Or are you forced to use both a vCPU ...
- 276
0
votes
2
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2k
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What Are VMware ESXi/vSphere Fault Tolerance Bandwidth Requirements
I plan on deploying a cluster of 2 ESXi/vSphere servers and having them run in fault tolerance mode. The virtual servers primarily be IIS & SQL. The physical servers will have a single Xeon E5-...
- 276
0
votes
2
answers
1k
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Microsoft licensing in a virtualized environment questions [duplicate]
I plan on deploying two physical servers which will run VMware ESXi and have a number of questions regarding Microsoft licensing. To note, all the VMs on the servers will be configured to run in ESXi'...
- 276
0
votes
2
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58
views
Can I control which DNS record a client application uses?
I'm trying to make our set of servers more fault tolerant. I have a web server, a mail server and a PBX server that uses SIP. I know that for each service, I can have the DNS return multiple A, MX ...
-1
votes
2
answers
106
views
What software should I use for fault tolerence/high availability for 2 servers [closed]
What are some of the industry standard enterprise software to allow fail-over or swap-over between 2 servers?
E.g., if 1 server goes down(due to connection or power, etc), the other kicks in either ...
- 103