So what's all this buzz around object based storage?

Object-Based Storage Device 

Object-Based Storage Devices (OSD) enable the creation of self-managed, heterogeneous, shared storage by moving low-level storage functions into the storage device itself and accessing the device through a standard object interface rather than a traditional block-based interface such as SCSI or IDE.  

Based on T10 OSD Specification

Intelligent storage increases horizontal scale

OSD Defined- SCSi Object Based Storage, peripheral deice type defined as OSD.

A storage object is a logical collection of bytes on a storage device with well known methods for access, attributes describing the characteristics of the data and security policies.

The difference between OSD and a block based device is the device interface. NOT THE PHYSICAL MEDIA BLOCK BASED DATA ACCESS -based on the physical block address.

2 components:

1.User component-presents logical data structures to the user applications

2.Storage component-manages the storage device manages the block meta data

Having these 2 separate components makes data sharing (sharing data blocks) between hosts very difficult.

BLOCK BASED DATA ACCESS -based on the physical block address:

Store( write block number) | Retrieve(read block number)

Devices relatively unintelligent and externally managed

Storage component manages meta data

FILE BASED DATA ACCESS:

Store(File) | Retrieve(Directory)

OBJECT BASED DATA ACCESS -based on the physical block address:

Store(DATA -->OID)| Retrieve(OID--> DATA )

OSD devices are intelligent and self managed

OSD devices are aware of the storage applications they serve

The most immediate effect of OSD is the offloading of space management. (Allocation and tracking of used & free blocks)

The interface OSD storage uses is very similar to a FILESYSTEM.

OSD manages the physical layout of the data (self management). Objects are created, deleted, read and written just like files are today With OSD management is offloaded to the storage device rather than the storage application. With OSD, in offloading the metadata to the storage device objects removes the dependency between metadata and the storage application.

With the metadata offloaded storage applications can now store their data structures as single objects rather than a collection of blocks.

OSD devices enables the creation of self-managed, heterogeneous, shared storage by moving low level storage functions into the storage device itself, rather that externally managed in block evices, and by acessing the device thru standard object interface rather than the block based interface such as SCSI or IDE. Self management benefits SAN and DAS.

Because the device can treat objects individually its easier to set security policies on a per object basis.

THE IMMMEDIATE BENEFIT OF OSD IS CROSS PLATFORM DATA SHARING IN A SAN.

THERE WOULD BE LITTLE BENEFIT WITH DIRECT ATTACHED STORAGE(DAS)

Posted at 09:08PM Nov 29, 2007 by gwaterson in Storage  |