Disks, Partitions, Volumes and RAID Performance with the Linux Operating System

Block devices in computer operating systems typically correspond to disks or disk partitions, and are used to store files in a filesystem. Disks are not the only real or virtual device which adhere to the block accessible stream of bytes block device model. Files, remote devices, or even RAM may be used as a virtual disks. This article examines several common combinations of block device layers used as virtual disks in the Linux operating system: disk partitions, loopback files, software RAID, Logical Volume Manager, and Network Block Devices. It measures their relative performance using different filesystems: Ext2, Ext3, ReiserFS, JFS, XFS,NFS

Volume Management in SAN Environment

Logical volume managers have long been key components of a storage system. Their key features are creation of logical or virtual views of physical storage devices and support for various software RAID levels. These make it possible to overcome the limits to capacity, availability and performance of a physical storage device. Most logical volume managers are operated in a single system environment. They are not adequate for SAN (storage area network) environments where several hosts share and access a logical volume at the same time. Some recent logical volume managers are run in a multi-host environment. However, they cannot support the enterprise computing environments in which the system must support 24*7*365 uptime operations such as online resizing and online backup. We propose a logical volume manager called \u27SANtopia Volume Manager\u27 that supports multihost environments and provides various volume management features to support enterprise computing. Also it is a cluster enabled logical volume manager that maximizes the parallelism for high performance, and provides high scalability and high availability

Ironman: Open Source Containers and Virtualization in bare metal

Trabalho de projeto de mestrado, Engenharia Informática (Engenharia de Software) Universidade de Lisboa, Faculdade de Ciências, 2021Computer virtualization has become prevalent throughout the years for both business and personal use. It allows for hosting new machines, on computational resources that are left unused, running as independent computers. Apart from the traditional virtual machines, a more recent form of virtualization was introduced and will be explored in this project, containers, more specifically Linux Containers. While multiple virtualization tools are available, some of them require a premium payment, while others do not support container virtualization. For this project, LXD, an open source virtual instance manager, will be used to manage both virtual machines and containers. For added service availability, clustering support will also be developed. Clustering will enable multiple physical computers to host virtual instances as if they were a single machine. Coupled with the Ceph storage back end it allows for data to be replicated across all computers in the same cluster, enabling instance recovery when a computer from the cluster is faulty. The infrastructure deployment tool Puppet will be used to automate the installation and configuration of an LXD virtualization system for both a clustered and non clustered environment. This allows for simple and automatic physical host configuration limiting the required user input and thus decreasing the possibilities of system misconfiguration. LXD was tested for both environments and ultimately considered an effective virtualization tool, which when configured accordingly can be productized for a production environment

Gollach : configuration of a cluster based linux virtual server

Includes bibliographical references.This thesis describes the Gollach cluster. The Gollach is an eight machine computing cluster that is aimed at being a general purpose computing resource for research purposes. This includes image processing and simulations. The main quest in this project is to create a cluster server that gives increased computational power and a unified system image (at several levels) without requiring the users to learn specialised tricks. At the same time the cluster must not be tasking to administer

LVM in the Linux environment: performance examination

Ovaj članak predstavlja ocjenjivanje svojstava LVM (Logical Volume Manager) sustava pod Linux operativnim sustavom. Rad uključuje matematički model vremena pristupa datotečnom sustavu sa i bez LVM opcije. Matematički model je validiran na primjeru Linux 32bit ext3, na kernel verziji 2.6, a na bazi usporedbe svojstava datotečnog sustava konfiguriranog za dva slučaja, sa i bez LVM. Mi smo generirali dvije LVM mogućnosti, istog kapaciteta, ali različite po složenosti unutarnje strukture. Svojstva su mjerena pomoću Postmark benchmark aplikacije koja simulira opterećenje Internet e-mail servera. Definirali smo tri vrste opterećenja, pri čemu uglavnom dominiraju relativno mali objekti. Rezultati ispitivanja su pokazali da je najbolja opcija da se koristi datotečni sustav bez primjene LVM. Benchmark rezultati su tumačeni na temelju matematičkog modela vrijemena pristupa datotečkom sustavu.This paper presents a performance evaluation of LVM (Logical Volume Manager) system under the Linux operating system. The presented work includes proposal of the mathematical modeling of file system access time with and without LVM option. A mathematical model is further validated for the case of 32bit Linux ext3 file system with kernel version 2.6, taking into consideration the comparison of a file system in two defined configurations, with and without LVM. We have created two LVM options, with the same capacity, but different in complexity of the internal structure. The performance is measured using the Postmark benchmarking software application that simulates workload of Internet mail server. We have defined three types of workloads, generally dominated by relatively small objects. Test results have shown that the best option is to use direct file system realization without applying LVM. Benchmark results are interpreted based on provided mathematical model of file system access time