LINUX FILESYSTEMS, PART 3 – JOURNALIZED FILESYSTEM – AIRBAG FOR SERVER CRASH

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This blog article details how a brutal interruption of a write operation can corrupt a whole filesystem and how a journal provides a protection against such incomplete writes. 3.1 Consequences of uncomplete writes When you write a file, the underlying filesystem is actually doing two different kinds of write operations: metadata and data writes. For […]

HOWTO: LINUX FILESYSTEMS

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This blog series aims to be a reference guideline by collecting useful knowledge and tutorials about Linux filesystems, mainly about ext3 and ext4. Because, as systems engineers/administrators, when we need to manually perform disk maintenance on a server, we know that a tiny mistake may have large consequences. “Trial-and-Error” is sometimes a good way to […]

ALL CLUSTER-NODES ARE EQUAL, BUT SOME ARE MORE EQUAL THAN OTHERS

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Hardware clustering is frequently used in computer systems where high availability and scalability are needed. In horizontal clustering the same application software is typically installed on multiple identical nodes. For web applications load balancing software such as Cisco’s ‘Global Site Selector’ is used to direct client requests to nodes based on rules (fig 1). The […]