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 –

Team Members Leader - Chris Hartley chrhartl@cisco.com Members ???

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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 ---

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

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” https://en.wikipedia.org/wiki/Logical_unit_number “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.” https://www.computerweekly.com/answer/What-is-a-LUN-and-why-do-we-need-storage-LUNs

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

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

Storage Virtualization https://en.wikipedia.org/wiki/Storage_virtualization Decoupling of the file system from the underlying hardware

References https://en.wikipedia.org/wiki/Logical_volume_management https://en.wikipedia.org/wiki/Storage_virtualization ceur-ws.org/Vol-1091/paper8.pdf http://cdmi.sniacloud.com/ http://occi-wg.org/about/specification/ http://wiki.illumos.org/download/attachments/1146951/zfs_last.pdf

DMTF CIM 2.48

SNIA Swordfish / DMTF Redfish https://www.snia.org/forums/smi/swordfish http://redfish.dmtf.org/schemas/swordfish/v1/ 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

Proposed Model – Package Dependencies Storage Equipment Core

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

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)

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

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

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 ?

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

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

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

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

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

Storage Examples – Linux LVM (6) Where can we store the LVM config ?? ComputePool decorator ? Storage Examples – Linux LVM (6) https://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux)

chris@ubuntu:~$ sudo fdisk -l … Disk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 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 * 2048 41940991 41938944 20G 83 Linux

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

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

Storage Examples – Lustre (7) http://lustre.org/ Storage Examples – Lustre (7)

Storage Examples – CEPH https://ceph.com Storage Examples – CEPH

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)