Here is a small right up.This should be on NOW tomorrow.
================
RAID implementation in Data ONTAP 6.0 and later ensure reliability by allocating every 64th block to store checksum data for the previous 63 blocks. This is referred to as 'Zone Checksums'. Data ONTAP 6.0.1R1 can also use a new RAID data checksum type to improves the efficiency of disk access. The new type is known as Block checksums . The block checksum feature is available on Fibre Channel StorageShelf F9 disk shelves, using disks formatted for block checksums.
Block Checksums is a volume level support and requires each disk to format to 520 bytes per sector, as opposed to the 512 bytes per sector formatting . The extra space is broken into two parts. The first is 4,096 bytes of file system data. The remaining 64 bytes contain the checksum data for the previous 4.096 bytes. In this manner the checksum is appended to each block of data.
The Block Checksums are supported in pre-formatted, 18GB,36GB and 72GB drives only on FC9 shelves.Note that this format is different than the drives shipped with previous versions of Data ONTAP OS. While the new drives can be added to a Zone Checksum Volumes the reverse is not true.
=================
Thanks!
-Puneet ___________
Chris Thompson wrote:
I've been reading the 6.0.1R1 "Start Here" document (for advance planning: we're not about to move to it) and especially the "New features in 6.0.1" section.
I wonder whether someone can explain how "block checksum" disks (and volumes) differ from "zoned checksum" ones, at a slightly more technical level than "block checksum disks are the ones with yellow front bezel ID labels and the orange system requirements labels on the side"? :)
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.