file layout การใช้

• As several filesystems, both native and non-native, are available under Unix, there is not one directory file layout.
• Files in an Autopackage archive are not easily extracted by anything other than Autopackage itself as the internal format must be parsed in order to determine file layout and other issues.
• One solution, employed by the WAFL file system ( Write Anywhere File Layout ) is to be lazy about making pages durable ( i . e . write-behind caching ).
• This style of versioning is essentially the inverse of tree versioning methods used by Write Anywhere File Layout ( WAFL ), ZFS and Btrfs, where multiple tree roots of an entire filesystem are created in order to express differences between versions of the filesystem.
• After the initial lookup of the file layout, the MDS is not involved in file IO operations since all block allocation is managed internally by the OST . Clients do not directly modify the objects on the OST filesystems, but instead delegate this task to OSS nodes.
• As the name suggests Write Anywhere File Layout does not store data or metadata in pre-determined locations on disk, instead it automatically places data using temporal locality to write metadata alongside user data in a way designed to minimize the number of disk operations required to commit data to stable disk storage using single and dual parity based RAID.
• For read or write operations, the client then interprets the file layout in the " logical object volume ( LOV ) " layer, which maps the file offset and size to one or more objects, each residing on a separate OST . The client then locks the file range being operated on and executes one or more parallel read or write operations directly to the OSS nodes.