saravananlinux

Storage pools and volumes are not required for the proper operation of guest virtual machines. Pools and volumes provide a way for libvirt to ensure that a particular piece of storage will be available for a guest virtual machine, but some administrators will prefer to manage their own storage and guest virtual machines will operate properly without any pools or volumes defined. NFS storage pool Suppose a storage administrator responsible for an NFS server creates a share to store guest virtual machines' data. T he system administrator defines a pool on the host physical machine with the details of the share (nfs.example.com:/path/to/share should be mounted on /vm _data). When the pool is started, libvirt mounts the share on the specified directory, just as if the system administrator logged in and executed m ount nfs.exam ple.com :/path/to/share /vm data. If the pool is configured to autostart, libvirt ensures that the NFS share is mounted on the directory specified when libvir...

A storage pool is a file, directory, or storage device managed by libvirt for the purpose of providing storage to guest virtual machines. T he storage pool can be local or it can be shared over a network. A storage pool is a quantity of storage set aside by an administrator, often a dedicated storage administrator, for use by guest virtual machines. Storage pools are divided into storage volumes either by the storage administrator or the system administrator, and the volumes are assigned to guest virtual machines as block devices. In short storage volumes are to partitions what storage pools are to disks. Although the storage pool is a virtual container it is limited by two factors: maximum size allowed to it by qemu-kvm and the size of the disk on the host physical machine. Storage pools may not exceed the size of the disk on the host physical machine. T he maximum sizes are as follows: virtio-blk = 2^63 bytes or 8 Exabytes(using raw files or disk) Ext4 = ~ 16 T B (using 4 KB block s...

Guest virtual machines running on a KVM hypervisor do not have dedicated blocks of physical RAM assigned to them. Instead, each guest virtual machine functions as a Linux process where the host physical machine's Linux kernel allocates memory only when requested. In addition the host physical machine's memory manager can move the guest virtual machine's memory between its own physical memory and swap space. T his is why overcommitting requires allotting sufficient swap space on the host physical machine to accommodate all guest virtual machines as well as enought memory for the host physical machine's processes. As a basic rule, the host physical machine's operating system requires a maximum of 4GB of memory along with a minimum of 4GB of swap space. T his example demonstrates how to calculate swap space for overcommitting. Although it may appear to be simple in nature, the ramifications of overcommitting should not be ignored. Refer to Important before procee...

In a live migration, the guest virtual machine continues to run on the source host physical machine while its memory pages are transferred, in order, to the destination host physical machine. During migration,KVM monitors the source for any changes in pages it has already transferred, and begins to transfer these changes when all of the initial pages have been transferred. KVM also estimates transfer speed during migration, so when the remaining amount of data to transfer will take a certain configurable period of time (10ms by default), KVM suspends the original guest virtual machine, transfers the remaining data, and resumes the same guest virtual machine on the destination host physical machine.

what the metadata is for. Your single file is split up into a bunch of small pieces and spread out of geographic location, servers, and hard drives. These small pieces also contain more data, they contain parity information for the other pieces of data, or maybe even outright duplication. The metadata is used to locate every piece of data for that file over different geographic locations, data centres, servers and hard drives as well as being used to restore any destroyed pieces from hardware failure. It does this automatically. It will even fluidly move these pieces around to have a better spread. It will even recreate a piece that is gone and store it on a new good hard drive.

mke2fs 1.41.12 (17-May-2010) Filesystem label= OS type: Linux Block size=4096 (log=2) -->Default block size 4KB. Fragment size=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 3276800 inodes, 13107200 blocks --> no of inodes & blocks created under that partition. 655360 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=4294967296 400 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks:         32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,         4096000, 7962624, 11239424 Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort. Today, it is more or less accepted that there are three Cloud Computing models depending on the type of service provided, IaaS, Infrastructure as a Service, PaaS, Platform as a Service, and SaaS, Software as a Service. IaaS – Infrastructure as a Service   Infrastructure as a Service provides infrastructure capabilities like processing, storage, networking, security, and other resources which allow consumers to deploy their applications and data. This is the lowest level provided by the Cloud Computing paradigm. Some examples of IaaS are: Amazon S3/EC2, Microsoft Windows Azure, and VMWare vCloud.   PaaS – Platform as a Service   Platform as a Service provides application infrastructur...

A filesystem is the methods and data structures that an operating system uses to keep track of files on a disk or partition; that is, the way the files are organized on the disk. The word is also used to refer to a partition or disk that is used to store the files or the type of the filesystem. Thus, one might say I have two filesystems meaning one has two partitions on which one stores files, or that one is using the extended filesystem, meaning the type of the filesystem. Before a partition or disk can be used as a filesystem, it needs to be initialized, and the bookkeeping data structures need to be written to the disk. This process is called making a filesystem . Most UNIX filesystem types have a similar general structure, although the exact details vary quite a bit. The central concepts are superblock , inode , data block , directory block , and indirection block . The superblock contains information about the filesystem as a whole, such as its size (the exact inform...