Feb 8, 2009
Volume Layouts in VxVM...
Non Layered Volumes In a non-layered volume, a subdisk is restricted to mapping directly to a VM disk Layered Volumes A layered volume is a virtual Veritas Volume Manager object that is built on top of other volumes by mapping its subdisks to underlying volumes. Hence it is called ‘volume on volume’. Volume layouts supported in VxVM Concatenation Concatenation maps data in a linear manner onto one or more subdisks in a plex. To access all of the data in a concatenated volume sequentially, data is first accessed in the first subdisk from beginning to end. Data is then accessed in the remaining subdisks sequentially from beginning to end, until the end of the last subdisk. Striping Striping maps data so that the data is interleaved among two or more physical disks. A striped plex contains two or more subdisks, spread out over two or more physical disks. Data is allocated alternately and evenly to the subdisks of a striped plex. Mirroring (RAID-1) Striping maps data so that the data is interleaved among two or more physical disks. A striped plex contains two or more subdisks, spread out over two or more physical disks. Data is allocated alternately and evenly to the subdisks of a striped plex. Striping plus mirroring (mirrored-stripe or RAID-0+1) The combination of mirroring above striping is called a mirrored-stripe layout. Mirroring plus striping (striped-mirror, RAID-1+0 or RAID-10) The combination of striping above mirroring. This combined layout is called a striped-mirror layout. RAID-5 (striping with parity) RAID-5 provides data redundancy by using parity. Parity is a calculated value used to reconstruct data after a failure. The data and calculated parity are contained in a plex that is “striped” across multiple disks |
Post a Comment