Wednesday, January 30, 2008
Clariion Disk Format
The Clariion Formats the disks in Blocks. Each Block written out to the disk is 520 bytes in size. Of the 520 bytes, 512 bytes is used to store the actual DATA written to the block. The remaining 8 bytes per block is used by the Clariion to store System Information, such as a Timestamp, Parity Information, Checksum Data.
Element Size – The Element Size of a disk is determined when a LUN is bound to the RAID Group. In previous versions of Navisphere, a user could configure the Element Size from 4 blocks per disk 256 blocks per disk. Now, the default Element Size in Navisphere is 128. This means that the Clariion will write 128 blocks of data to one physical disk in the RAID Group before moving to the next disk in the RAID Group and write another 128 blocks to that disk, so on and so on.
Chunk Size – The Chunk Size is the amount of Data the Clariion writes to a physical disk at a time. The Chunk Size is calculated by multiplying the Element Size by the amount of Data per block written by the Clariion.
128 blocks x 512 bytes of Data per block = 65,536 bytes of Data per Disk. That is equal to 64 KB. So, the Chunk Size, the amount of Data the Clariion writes to a single disk, before writing to the next disk in the RAID Group is 64 KB.