Guaranteeing Storage Performance in CloudStack

Mike Tutkowski- Full-time CloudStack software engineer, CloudStack PMC member

- Focused on CloudStack's storage component

SolidFire (http://solidfire.com)- Based out of Boulder, CO

- Develop a clustered, scale-out SAN technology (using industry-standard hardware)

- Built from the ground up to support guaranteed Quality of Service (QoS) on a per-volume (LUN) basis (min, max, and burst IOPS per volume)

- All SSD architecture (no spinning disks)

- Leverage compression, de-duplication, and thin provisioning (all inline) on a 4-KB block boundary across the entire cluster to drive down cost/GB to be on par with traditional disk-based SANs

- Rest-like API to enable automation of all aspects of the SAN

CloudStack from the top down (prior to 4.2)

Primary Storage Secondary Storage

Objectives Storage for VMs (root and data disks) Data to be stored for future retrieval

Use Cases • Production Applications• Traditional IT Systems• Database-Driven Apps• Messaging / Collaboration• Dev/Test Systems

• VM Templates• ISO Images• Backups of Volumes

Workloads • High-Change Content• Smaller, Random R/W• Higher / “Bursty” IO

• Typically More Static Content• Larger, Sequential IO (more read

than write)• Lower IOPS

Storage Use Cases & Workloads

• Primary Storage is associated with a cluster

• A cluster can access more than one Primary Storage

• Primary Storage can be shared among hosts or local to a host

● Primary Storage stores the disk volumes (both root and data disks) for all the VMs in that cluster

• Depending on hypervisor type, there are several ways to configure Primary Storage (we shall take a look at XenServer)

What is Primary Storage (Pre 4.2)?

• Admin allocates space ahead of time on the storage system(Example: Create a volume on the SolidFire SAN)

• Admin defines a storage resource in the hypervisor(Example: Create a XenServer Storage Repository)

• Admin defines a storage pool in CloudStack(Example: Create Primary Storage in CloudStack for a cluster)

• Admin creates a Compute Offering using the Primary Storage(Example: 1 vCPU, 2 GB RAM, 50 GB)

Provisioning Primary Storage (Pre 4.2)

Allocate Storage on the SolidFire SAN

Define the Storage Resource in the Hypervisor

Select the type of the storage repository

Name the storage repositoryStorage repository is now available in the hypervisor

Map the storage repository to the volume

Define a Primary Storage Pool in CloudStack

Add Primary Storage Define Primary Storage

Primary Storage Available for Use

Create a Compute Offering in CloudStack

Compute Offering Available for Use

Add Compute Offering Define Compute Offering

Primary Storage in CloudStack >= 4.2

• Fully automated provisioning through CloudStack

• Dynamic volume creation for VM root disks and additional data disks

• With SolidFire each volume receives guaranteed IOPS

Provide a way to expose vendor-unique features within CloudStack

Eliminate the need for customers to create additional orchestration logic to provision storage

Have the ability to defer the creation of a volume until the moment the end user elects to execute a Compute or Disk Offering

My Specific Needs from the Plug-in

Creating Primary Storage Based on a Plug-in

http://127.0.0.1:8080/client/api?command=createStoragePool&

scope=zone&

zoneId=cf4e6ddf-8ae7-4194-8270-d46733a52b55&

name=SolidFire_121258566&

url=MVIP%3D192.168.138.180%3A443%3BSVIP%3D192.168.56.7%3BclusterAdminUsername%3Dadmin%3BclusterAdminPassword%3Dpassword%3BclusterDefaultMinIops%3D200%3BclusterDefaultMaxIops%3D300%3BclusterDefaultBurstIopsPercentOfMaxIop%3D2.5&

provider=SolidFire&

tags=SolidFire_SAN_1&

capacityIops=4000000&

capacityBytes=2251799813685248&

hypervisor=Any&

response=json

Primary Storage Based on a Plug-in

Creating Disk Offerings with the Plug-in

--OR--

Admin-Defined QoS

Customer-Defined QoS

• Orchestrated through CloudStack• Administrator-defined size (GBs) and QoS (IOPS)• Customer-defined size (GBs) and QoS (IOPS)

Add Disk Offering

New Disk Offerings

Admin-Defined QoS

Customer-Defined QoS

--VS--

Admin-Defined QoS

• Orchestrated through CloudStack• Based on Disk Offerings• Administrator-defined QoS (IOPS)• Customer-defined QoS (IOPS)

Customer Adds a Volume

Customer-Defined QoS

Add a Volume

Customer Attaches the Volume to a VM

• Choose the Volume to be Attached

• Click Attach Disk

• Select the VM Instance

What Happens on the SolidFire SAN?

The Volume is Created

The Volume's QoS Settings are Defined

What Happens on the Hypervisor?

The Storage Repository is Created

Notes• ESX works in a similar fashion to XenServer.

● Instead of a storage repository, a datastore is created.● Instead of a VDI inside of a storage repository, a VMDK file is created inside of a datastore.

• Dynamic creation of backend volumes (LUNs) for data disks supported with KVM in CloudStack 4.3.● iscsiadm is used within the KVM agent to log in to the iSCSI target.● Libvirt is used to attach the new device to a VM.

• Hypervisor snapshots (for data disks) are supported for XenServer and ESX in 4.3.● A new field has been introduced that allows admins to specify how much additional space, if any,

should be set aside for hypervisor snapshots of the disk in question.● For SolidFire, there is very little overhead associated with creating, say, a 8 GB volume (LUN)

versus, say, a 8 TB volume (LUN).

● Dynamic creation of backend volumes (LUNs) for root disks supported for XenServer and ESX in 4.4 (along with hypervisor snapshots).● Applicable template copied to new backend volume (LUN).● Due to SolidFire's de-duplication, this amounts to very little SSD interaction.

4.6 Backend-Snapshot Development• Adding support for backend snapshots (targeting XenServer and ESX first).

● Due to the way a XenServer storage repository is structured, I cannot technically use SolidFire snapshots to implement this feature.

● When a CloudStack snapshot of a volume is requested:● Create a new SolidFire volume with the same characteristics as the volume containing the VDI

that CloudStack wants to snapshot.● Tell XenServer to create a VM snapshot of the VDI we're interested in.● Attach the new SolidFire volume (LUN) and have XenServer create a new SR on it.● Copy the snapshot VDI to the new SR (which is backed by the new SolidFire volume (LUN)).● Delete the snapshot VDI on the original SR.● Detach the new SR from XenServer (the SolidFire volume (LUN) now contains a copy of the

correct VDI (with a unique UUID for the new SR and another unique UUID for the VDI)).

(If the VDI CloudStack wants to take a snapshot of is on a detached volume, this code will attach the SR that contains the VDI before performing step 2. Once copying of the data from one SR to the other has completed, the source SR will be detached from XenServer.)

1620 Pearl Street,Boulder, Colorado 80302

Phone: 720.523.3278Email: info@solidfire.com

www.solidfire.com