XAM and OSD

J Jensenhepsysman RAL June 2008

Filesystem

Device

Middleware/Apps

open(), fopen()

Kernel

scsi etc

Filesystem

Device

Middleware/Apps

Kernel

File

Filesystem

Device

Middleware/Apps

Kernel

File metadata

File

Filesystem

Device

Middleware/Apps

Kernel

File

metadata

File

File

metadata

metadata

Filesystem

Device

Middleware/Apps

Kernel

File

metadata

File

File

metadata

metadata

Introducing OSD

• Object Storage Devices• SNIA (www.snia.org)• Standardisation: ANSI T10

(www.t10.org)

Filesystem

Device

Kernel

Filemetadata

Device stores objects rather than blocksKnows about metadataDevices do space management & security

object

DeviceFile

metadata

Panasas

Lustre

• Consistent view, enforced at low level• Improve scalability and performance

object

OSD Feature(sets)

• Object creation/access (duh)

• Meta: format, list, flush (partial (v2))

• Data Security– Integrity, in-flight enc

• 64 bit friendly CDB (v2)

• Device security– CDB capabilities (v2)

• Groups (collections)– Bulk ops (v2)

• Partition mgmt– Clone/snapshot (v2)

• Exception mgmt (v2)

eXtensible Access Method

• API• Metadata• Records• Querying

Filesystem

Middleware/Apps

Kernel

File

metadata

File

File

metadata

metadata

• Storage system can access metadata– Recovery– Device data is meaningful– ILM

XSet - XAM Objects

• Hierarchical• XLibrary

> XSystem > XSet

XAM to OSD

• Recommendation – XSet to Object– Names stored as OSD attributes– Different options for properties

• Functions to commands• Management policies• Ongoing work…