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Questions tagged [fault-tolerance]

The tag has no usage guidance.

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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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0answers
10 views

What is optimal hardware configuration for LAMP video application [duplicate]

I need to run Linux-Apache-PHP-MySQL video application (Video calling platform) for a 40 concurrent video calls - I am aiming 120 users (3 on a video call so there will be 40 concurrent video calls ...
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2answers
71 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 ...
0
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1answer
34 views

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 ...
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0answers
29 views

Is it an anti-pattern to send an async message to “yourself”

For fault tolerance and reliability, sometimes in our architecture we opt to have a service send a message to an SQS queue which it consumes from itself. It's sort of like a durable asynchronous way ...
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0answers
39 views

Fault Tolerance Patterns with message publishers SNS and SQS

In a theoretical scenario where I wish to notify 2 systems about some type of event via a message, I have considered two patterns - although I'm sure many others also exist. Publish 2 distinct ...
0
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2answers
85 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 ...
3
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1answer
172 views

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 ...
1
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1answer
607 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 ...
1
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2answers
58 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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1answer
36 views

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 ...
0
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1answer
1k views

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, ...
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1answer
1k views

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 ...
6
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1answer
153 views

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 ...
1
vote
1answer
390 views

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 ...
6
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3answers
4k 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 ...
1
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1answer
382 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 ...
0
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1answer
75 views

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?
0
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1answer
54 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'...
10
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1answer
6k 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 "...
2
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2answers
289 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 ...
0
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1answer
5k views

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?
2
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3answers
575 views

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 ...
3
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1answer
930 views

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 ...
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0answers
189 views

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 ...
1
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0answers
45 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 ...
4
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1answer
438 views

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 ...
2
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1answer
1k 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 ...
0
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1answer
747 views

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 ...
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2answers
237 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 ...
1
vote
1answer
938 views

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
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0answers
387 views

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 ...
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2answers
502 views

pfsense CARP - wan failure on firewall

I have recently configured 2 firewall (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 ...
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1answer
64 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 ...
2
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2answers
722 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 ...
8
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3answers
9k 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 ...
2
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2answers
2k views

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 ...
0
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1answer
1k views

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 ...
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2answers
2k views

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-...
0
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2answers
873 views

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'...
0
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2answers
49 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 ...
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2answers
82 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 ...
2
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1answer
757 views

What is the importance of “RpcClientAccessServer” on a database in an Active/Active stretched DAG?

I have two sites with a stretched DAG between them. By "sites" I mean two AD sites that correspond with different physical and network circuits. When I take an individual mailbox database and move ...
0
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1answer
425 views

RAID 5 - DELL 2850 and others

I have installed Ubuntu on a DELL 2850 and I have configured an array of 5 disks (SCSI 73GB 10K) in RAID5. I wanted to simulate a drive error so in the middle of something I just took one of the ...
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2answers
1k views

Dell PERC H700 and 8 disk slots : what are my options to increase disk fault tolerance?

We've got a Dell PowerEdge T510 which has 8 disk slots in the front. It is currently utilising 6 of these slots, and the disks are controlled by a PERC H700 controller. The disks are currently running ...
1
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1answer
602 views

Advantage of Microsoft Cluster over Microsoft Network Load Balancer

Till recently, I assumed that Microsoft NLB worked at an OS/Machine level rather than an Application Level. i.e. the NLB just monitors heartbeats on the machine to check if machine is alive and then ...
4
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1answer
263 views

What TLDs should I use for my NS records for redundancy? (DNSSEC support required)

Question As a general practice, is it a good idea to use multiple TLDs for the name servers? How should I choose between which TLD would be a good candidate for being the root server for my NS name?...
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2answers
2k views

Record DNS for 2 static ip - fault tolerance

i've a web server in a DMZ reachable from 2 different public static ip addresses provided by 2 different internet connection by 2 different ISPs. I want to create a record let's say "myserver.contoso....
1
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1answer
212 views

Why state is needed for keepalived

From the doc ! MASTER and BACKUP state are determined by the priority ! even if you specify MASTER as the state, the state will ! be voted on by priority (so if your state is MASTER but your ! ...
1
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2answers
179 views

Stratus Servers vs Virtualised Machines as a High Availability Solution [closed]

I've been asked to do this as a presentation, but to be honest, either I've totally missed the point or am I being asked to compare an actual company i.e. Stratus against the concept of virtualising ...