1. Task 36a Scope – Storage (L=ChrisH)
Purpose – add Storage support to the model
Specifically – Block, File and Object storage support, both directly attached and over a network
Includes –
Excludes – Storage physical inventory, which is covered by the existing Equipment model. Excludes Compute (CPU and Memory)
External Dependencies –
Assumptions –
Risks –

2. Team Members
Leader - Chris Hartley
Members
???

3. IPR Declaration Is there any IPR associated with this presentation NO
NOTICE: This contribution has been prepared to assist the ONF. This document is offered to the ONF as a basis for discussion and is not a binding proposal on Cisco or any other company. The requirements are subject to change in form and numerical value after more study. Cisco specifically reserves the right to add to, amend, or withdraw statements contained herein.
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4. Need for a Storage Model
This is part of the data center triad :
Compute  partially done
Network  Done
Storage  this pack
Information
Transfer
Modification N Y
Storage
Network
Compute
---

5. Particular Scenarios we wish to support
We should support the 3 different types of storage :
Block storage
File storage
Object storage
We should support standalone hosts with local storage, raid, SCSI as well as network based storage, including enterprise and cloud storage
The big difference as storage scales up is the pooling / clustering and partitioning
Similar to the rest of the model, we need to separate physical storage from logical storage

6. Storage challenges - terminology
A big issue is that there is no single standard terminology
For example, the definition of a LUN is problematic
Is it a Logical Unit Number (just the number) ?
A Logical Unit ?
“A LUN, is a number used to identify a logical unit, which is a device addressed by the SCSI protocol or Storage Area Network protocols which encapsulate SCSI, such as Fibre Channel or iSCSI”
“a logical unit number (LUN) is a slice or portion of a configured set of disks that is presentable to a host and mounted as a volume within the OS.”

7. Storage challenges - diversity
Another issue is the diverse range of solutions
For example, just in the storage networking space there are a large number of options, some of which are shown on the next slide

8. SAN Storage Area Network
Storage Options
DAS Direct Attached
NAS Network Attached
SAN Storage Area Network
Object Storage
Operating System
Operating System
Operating System
Operating System
File I/O
File I/O
File I/O
File I/O
File System
File System
File System
SCSI
CIFS/NFS (SMB)
iSCSI/FC/FCoE
iFCP/FCIP/InfiniBand
REST/SOAP
Network
File System
File System
Block I/O
Block I/O
Block I/O
Block I/O
Block Storage

9. Storage Virtualization
Decoupling of the file system from the underlying hardware

10. References https://en.wikipedia.org/wiki/Logical_volume_management
ceur-ws.org/Vol-1091/paper8.pdf

11. DMTF CIM 2.48

12. SNIA Swordfish / DMTF Redfish
The key RedFish concepts appear to be :
Drive - a single physical disk drive for a system
Simple Storage - a storage controller and its directly-attached devices
Storage - storage subsystem represents a set of storage controllers (physical or virtual) and the resources such as volumes that can be accessed from that subsystem
Volume - a volume, virtual disk, LUN, or other logical storage entity

13. Proposed Model – Package Dependencies
Storage
Equipment
Core

14. Proposed Model
Note that we don’t actually communicate directly with the disk platter, even for local storage, we are actually communicating with the (implicit) controller

15. Compute Pool
Note that the decision was made to have a single compute pool rather than separate Storage, CPU and memory pools, because
CPU and memory are usually tightly coupled and the pool can then allocate these consistently
Sometimes storage is tightly coupled with CPU and memory and the pool can then allocate these consistently
Storage, CPU and memory may not be the best grouping of the pool entries – perhaps physical vs logical, input vs output – starting with a flat set of all the pool entries will allow the best grouping to evolve
Note that the pools aren’t hierarchical (deliberately no ComputePool contained in self-join)
The associations XxxPoolEntryIsLogical allow an output from one pool to become the input of another pool
We really want this to form a directed acyclic graph (no loops)

16. Storage Examples – Single Disk (1)
A computer with two disks would have this entire set of objects repeated
This model representation has some inefficiencies for the sake of consistency

17. Storage Examples – Partitioned Single Disk (2)
For example Windows C: and D: drives on the one physical disk

18. Storage Examples – RAID 1 Mirror (3)
Modelling the RAID controller is optional
Other RAID options with a single FileSystem would be similar but with more disks
Where can we store the RAID type ?? And other RAID config attributes ??
ComputePool decorator ?

19. Storage Examples – Partitioned RAID 1 Mirror (4)
RAID controller not shown
Here the disk array has been partitioned into two file systems. Again this can be extended for other disk array options

20. Storage Examples – Hosted Vmm {type-2} virtual Disk (5)
Where can we store the virtual disk config attributes ??
ComputePool decorator ?
Note the Hypervisor support is not shown

21. Alternating Combining and Partitioning
Combine
Partition
Note split here is orthogonal to combine

22. Linux Logical Volume Manager
Volume Group
Disk
Disk Partition
Logical Volume
‘Big Aggregator in the middle’

23. Linux Logical Volume Manager mapped to the model
Disk
Disk Partition
Volume Group
Logical Volume
cp1
cp4
cp = ComputePool instance
cp2
cp3

24. Storage Examples – Linux LVM (6)
Where can we store the LVM config ??
ComputePool decorator ?
Storage Examples – Linux LVM (6)

25. chris@ubuntu:~$ sudo fdisk -l…
Disk /dev/sda: 20 GiB, bytes, sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x6b5fd3ef
Device Boot Start End Sectors Size Id Type
/dev/sda1 * G 83 Linux

26. Network Storage Examples – NAS (8)
Here we treat the network storage as an appliance

27. Network Storage Examples – NAS (8b)
Board with CPU to convert between storage network protocols and SATA
SATA Drive with controller and buffer
Network Storage Examples – NAS (8b)
Network Port
This is just a more detailed variant of the previous example
HBA Port
Drive Controller Port
Controllers not shown

28. Storage Examples – Lustre (7)
Storage Examples – Lustre (7)

29. Storage Examples – CEPH
Storage Examples – CEPH

30. Storage Examples – CIFS NFS Shares
CIFS and NFs servers share via directories
Clients may import the shared directory as a ‘drive’ (Windows) or as a directory (Linux)