File striping

OneFS uses an Isilon cluster's internal network to distribute data automatically across individual nodes and disks in the cluster. OneFS protects files as the data is being written. No separate action is necessary to protect data.

Before writing files to storage, OneFS breaks files into smaller logical chunks called stripes. The size of each file chunk is referred to as the stripe unit size. Each OneFS block is 8 KB, and a stripe unit consists of 16 blocks, for a total of 128 KB per stripe unit. During a write, OneFS breaks data into stripes and then logically places the data into a stripe unit. As OneFS writes data across the cluster, OneFS fills the stripe unit and protects the data according to the number of writable nodes and the specified protection policy.

OneFS can continuously reallocate data and make storage space more usable and efficient. As the cluster size increases, OneFS stores large files more efficiently.

To protect files that are 128KB or smaller, OneFS does not break these files into smaller logical chunks. Instead, OneFS uses mirroring with forward error correction (FEC). With mirroring, OneFS makes copies of each small file's data (N), adds an FEC parity chunk (M), and distributes multiple instances of the entire protection unit (N+M) across the cluster.