User:Seann M

Striping

Stripe Unit Size – Size of each file chunk

Stripe Width - # of devices a file is written across

•	Stripe Width is determined by the number of nodes, the size of the file and protection settings.

OneFS block = 8 kB

128 kB written to each node

8 kB block size 8 x 16 blocks = 128 kB stripe unit size

•	As cluster size increases larger files are stored more efficiently

•	Due to OneFs parity technique files 128 kB and smaller are mirrored

'''Storage protection '''

Parity - An additional binary digit, the parity bit, is added to a group of bits that are moved together. This bit is used only for the purpose of identifying whether the bits being moved arrived successfully. Before the bits are sent, they are counted and if the total number of data bits is even, the parity bit is set to one so that the total number of bits transmitted will form an odd number. If the total number of data bits is already an odd number, the parity bit remains or is set to 0. At the receiving end, each group of incoming bits is checked to see if the group totals to an odd number. If the total is even, a transmission error has occurred and either the transmission is retried or the system halts and an error message is sent to the user.

Mirroring (via RAID definition) - RAID (redundant array of independent disks; originally redundant array of inexpensive disks) is a way of storing the same data in different places (thus, redundantly) on multiple hard disks. By placing data on multiple disks, I/O (input/output) operations can overlap in a balanced way, improving performance. Since multiple disks increases the mean time between failures (MTBF), storing data redundantly also increases fault tolerance.

Nodes

•	When a client connects to a node and writes that node acts as the “quarterback for the data layout. Inodes

•	Metadata that stores information mapping file location on disk, file protection settings, timestamp info.

•	Protected according to the files they reference

•	Distributed throughout the cluster and without need of reserved space

MCP

•	Coordinates and propagates the configuration changes that are applied to the cluster

•	Can be written in XML

/ifs

•	Root system for all file system data •	Available space listed as raw OneFS •	Operating System built on BSD the EFS file system and called through the kernel's VFS API.

•	Uses Unix style permissions on the cluster

Sharing

NFS v3 (some NFS v2 UDP support)

CIFS (SMB)

FTP

HTTP

•	Default sharing is via CIFS NFS

•	"isi services" command can enable/disable sharing