Ceph – full blown NVMe cluster

Ceph is open source software designed to provide highly scalable object-, block- and file-based storage under a unified system. Ceph storage clusters are designed to run on commodity hardware, using an algorithm called CRUSH (Controlled Replication Under Scalable Hashing) to ensure data is evenly distributed across the cluster and that all cluster nodes can retrieve ...

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Pacemaker and Corosync HA

In this setup we will setup a HA failover solution using Corosync and Pacemake, in a Active/Passive setup. Installation and Setup Prerequisites Hosts or DNS resolvers NTP Must be installed and configured on all nodes [code]cat /etc/hosts 10.0.1 10 ha1 server01 10.0.1.11 ha2 server02 [/code] Installation We will install pacemaker, it should install corosync as ...

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CGN: Carrier-grade NAT

Every network engineer with some experience knows RFC1918 address space from the top of their head. So no need to explain that almost every office, home user and some datacenter networks are using IP’s from this RFC. So far, so good. But, what if you have a large network with more then 10 physical locations ...

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Ceph TCP Performance Tuning Ubuntu

Below are a few TCP tunables that I ran into when looking into TCP performance tuning for CEPH based on our 10Gbit configuration. [code]# 10GE/32MB (33554432) #net.core.rmem_max = 33554432 #net.core.wmem_max = 33554432 #net.core.rmem_default = 33554432 #net.core.wmem_default = 33554432 #net.core.optmem_max = 40960 #net.ipv4.tcp_rmem = 4096 87380 33554432 #net.ipv4.tcp_wmem = 4096 65536 33554432 # 10GB/54MB (56623104) net.core.rmem_max ...

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Ubuntu Bonding with LACP

Linux allows us to bond multiple network interfaces into single interface using a special kernel module named bonding. The Linux bonding driver provides a method for combining multiple network interfaces into a single logical “bonded” interface. [code]sudo apt-get install ifenslave-2.6[/code] Now, we have to make sure that the correct kernel module bonding is present, and ...

Samsung’s Smart TV Smart Hub platform onbereikbaar – Wereldwijde uitval

Samsung Smart TV-eigenaren melden op twitter dat hun Smart TV functionaliteit niet meer werkt. De Samsung SmartHub software op de televisie meldt het is niet in staat om verbinding te maken met internet. Gebruikers melden dat ze zijn verbonden met hun (draadloos) netwerk en hun TV dit ook als zodanig laat zien, maar de tv blijft melden geen ...

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The internet is broken?

Yesterday, 12th of Aug 2014, the internet grew passed the 512.000 BGP Routes. This was not something new, Cisco warned about this in May 2014: It wasn’t that long ago (2008) that the table reached 256k routes, triggering action by network administrators to ensure the continued growth of the Internet. Now that the table has ...

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htaccess Redirect (non-www to www)

Currently i am actively improving our SEO rating by tweaking our website, servers and the URL. One important step is to use a redirect (301 redirect) when users enter the website with www in front of the address. Reason for this is because google will see www.wipa.nl and wipa.nl as two seperate websites. This hurts ...

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Configure multipath FC on Debian (HP EVA, Brocade dual 8GB FC)

This detailed how to guides to high availability and performance on Debian/Ubuntu for with a dual FC HBA (Brocade) and shared storage on a HP EVA6300.  Tested on Debian Linux 5.x and 6.x bits running on HP Proliant Dl360 and DL380 models, with 8GB FC Host Bus Adapters from Brocade. Configure the software we need ...

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Configuration of HP IRF (Intelligent Resilient Framework)

HP’s Intelligent Resilient Framework (IRF) is an advanced technology that allows one to virtualize 2 or more switches into a single switching and routing system also known as a “virtual switch”. IRF is available on the new HP A series switches such as the A5120 model and the A5500-5800 models. From Wikipedia: Intelligent Resilient Framework ...

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