XenServer Storage Integration Deep Dive

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XenServer

Storage Integration Deep Dive XenServer

Storage Integration Deep Dive

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Agenda

XenServer 5.5 Storage Architecture Multipathing

Vendor Integration

StorageLink

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Enterprise Edition Platinum

Edition

Edition Free

XenServer Essentials

Shared Storage (iSCSI, FC, NFS) XenCenter Management 64bit, Windows, Linux Workloads

Live Migration (XenMotion)

No socket restriction High Availability

StorageLink

^TM

Provisioning Services (p+v) Lab Management

Performance Monitoring

Citrix XenServer & Essentials 5.5 Family

Active Directory Integration Generic Storage Snapshotting Provisioning Services (virtual)

Stage Management

Workload Balancing

Workflow Studio Orchestration

NEW NEW

NEW

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XenServer 5.5

Storage Architecture XenServer 5.5

Storage Architecture

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Expanded Backup Support

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Storage Technologies

Storage Repository LUN

LVM Volume Group

LVM Logical Volume

Storage Repository Filesystem

.VHD file

Storage Repository LUN

LVM Volume Group

LVM Logical Volume

VHD header VHD header

XenServer 5.0 / 5.5 NFS / EXT3

XenServer 5.0 iSCSI / FC

XenServer 5.5 iSCSI / FC

VM virtual disk

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LVM XenServer 5.5 (LVHD)

• Replaces LVM for SRs

• Hosts VHD files directly on LVM volumes

• Best of both worlds

• Features of VHD

• Performance of LVM

• Adds Advanced Storage features

• Fast Cloning

• Snapshots

• Fast and simple upgrade

• Backwards compatible

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Multipathing

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Why using Multipathing?

• Path redundancy to storage

• Performance increase by load sharing algorithms

• Many fibre channel environments by default have multiple paths

FC HBA 2

FC HBA 1

XenServer FC Switches Storage Subsystem

LUN 1

Storage controller 1

Storage controller 2

LUN 1

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Enabling Multipathing

• xe host-param-set other- config:multipathing=true uuid=host_uuid

• xe host-param-set other-

config:multipathhandle=dmp uuid=host_uuid

• Note: Do not enable

multipathing by other ways

(e.g. CLI)!!!

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XenServer supports 2 multipathing technologies

Device Mapper Multipathing (DMP) RDAC MPP (mppVhba)

Default yes no

XenServer version >= 5.0

4.1 CLI >= 5.0 Update 2

Management by XenCenter yes no

Support wide storage range only LSI controller based storage

Driver / Daemon multipathd mppVhba driver

CLI path check multipath –ll mpputil

Configuration /etc/multipath-enabled.conf /etc/mpp.conf

(requires execution of

/opt/xensource/bin/update-initrd)

See details: http://support.citrix.com/article/ctx118791

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DMP vs RDAC MPP

• Check if RDAC MPP is running

• lsmod | grep mppVhba

• „multipath –ll“ would show MD device as output (if DMP is active)

• Use only 1 technology

• When RDAP MPP is running use it

• Otherwise use DMP

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MPP RDAC: Path check

• mpputil

Lun #0 - WWN: 600a0b80001fdf0800001d9c49b0caa1 ---

LunObject: present DevState: OPTIMAL Controller 'A' Path

---

Path #1: LunPathDevice: present

DevState: OPTIMAL Path #2: LunPathDevice: present

DevState: OPTIMAL Controller 'B' Path

---

Path #1: LunPathDevice: present

DevState: OPTIMAL Path #2: LunPathDevice: present

DevState: OPTIMAL

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DMP: Path check

• Monitoring using XenCenter

• Monitoring using CLI

• ^Command: multipath -ll

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Multipathing & Software iSCSI

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iSCSI with Software Initiator

• IP addressing to be done by XenServer Dom-0

• Multipathing also to be done by XenServer Dom-0

• Dom-0 IP configuration is essential

NIC 1

XenServer Switches Storage Subsystem

LUN 1 Storage

LAN Ctrl 1

IP

LUN 1

XenServer Dom-0

LUN

IP

1 LUN

IP

1

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Best practice configuration:

iSCSI storage with multipathing

• Separation of subnets also on IP base

NIC 2 NIC 1

XenServer FC Switches Storage Subsystem

LUN 1 Storage

LAN Adapter 1

Storage LAN Adapter 2 Port 1 IP:

192.168.1.201 Port 2 IP:

192.168.2.201 Port 1 IP:

192.168.1.202 Port 2 IP:

192.168.2.202 NIC 1 IP:

192.168.1.10 NIC 2 IP:

192.168.2.10 Subnet:

255.255.255.0 Subnet 1

Subnet 2

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Subnet 1

Not recommended configurations for multipathing and iSCSI:

NIC 2 NIC 1

XenServer

NIC 1 IP:

192.168.1.10 NIC 2 IP:

192.168.1.11 Both server NICs in same subnet

Subnet 1

NIC 2 NIC 1

XenServer

Team IP:

192.168.1.10 Mixing of NIC teaming and multipathing

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Multipathing with Software Initiator XenServer 5

• XenServer 5 supports Multipathing with iSCSI software initiator

• Prerequisites are:

• iSCSI target uses same IQN on all ports

• iSCSI target ports operate in portal mode

• Multipathing reliability has been enhanced

massively in XenServer 5.5

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How to check if iSCSI target operates in portal mode?

• Execute

iscsiadm -m discovery --type sendtargets --portal <ip address of 1 target>

• Output must show alls IPs of the target ports with identical IQN

• Example:

192.168.0.161:3260,1 iqn.strawberry:litchie 192.168.0.204:3260,2 iqn.strawberry:litchie

• When connecting to iSCSI target using XenCenter Storage

Repository Wizard, also all target

IPs should show up after Discovery

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NetApp Integration

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NetApp Storage

• NetApp Storage supports Multipathing

• For configuring NetApp storage and modification of multipath.conf see whitepaper

http://support.citrix.com/article/CTX118842

• NetApp typically supports portal mode for iSCSI

 multipathing for iSCSI SW Initiator is supported

• Especially for low-end NetApp storage (e.g. FAS2020) with

limited LAN adapters special considerations take place

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NetApp low-end storage (iSCSI)

• Often limited by NIC configuration

• Example: 2 NICs per head

• 1 aggregate / LUN is represented by 1 head at a time (other head for fault tolerance)

• Thus: 2 NICs effectively can be used for storage connection

• Typically Filer delivers non-block-based protocols (e.g. CIFS) which also require redundancy as well as block based

protocols (e.g. iSCSI)

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iSCSI Network

NIC 1 NIC 0

NIC 0 NIC 1

Controller 0

(active)

CIFS Network

NIC 0 NIC 1

Controller 1

(fault tolerance)

Example FAS2020: Scenario 1

no network reduncancy for iSCSI and CIFS

separation of networks

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Example FAS2020: Scenario 2

network redundancy for iSCSI and CIFS no separation of networks

NIC 1 NIC 0

NIC 0 NIC 1

Controller 0

(active)

CIFS & iSCSI Network

NIC Bond vif /

bond

NIC 0 NIC 1

Controller 1

(fault tolerance)

vif /

bond

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Example FAS2020: Scenario 3

network redundancy for iSCSI (multipathing) and CIFS separation of networks

NIC 1 NIC 0

NIC 0 NIC 1

Ctrl 1

(active) NIC Bond

Vif / bond Controller 1

(fault tolerance) Same configuration

CIFS VLAN iSCSI VLAN

NIC 3 NIC 2 Multipathing

CIFS VLAN

iSCSI VLAN

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Dell / Equalogic Integration

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Dell Equalogic Support

• XenServer 5.5 includes Adapter (min. firmware 4.0.1 required)

• Redundant path configuration does not depend on using adapter or not

• All PS series are supported as running same OS

• StorageLink Gateway support

planned

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Dell / Equalogic

• See whitepaper for Dell / Equalogic storage http://support.citrix.com/article/CTX118841

• Each Equalogic has two controllers

• Only 1 controller is active

• Uses „Group ID“ address on storage side (similar to bonding / teaming on server side)

• Only connection over group ID, no direct connection to the iSCSI ports possible

• Therefore multipathing cannot be used  bonding on XenServer side

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Datacore Integration

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Multipathing architecture with Datacore

• Different IQNs for targets – no portal mode possible!!

NIC 2 NIC 1

XenServer Switches

LUN 1 Storage

Controller 1

Storage Controller

2 Port 1 IP:

192.168.1.201 Port 2 IP:

192.168.2.202 NIC 1 IP:

192.168.1.10 NIC 2 IP:

192.168.2.10 Subnet:

255.255.255.0 Subnet 1

Subnet 2

IQN 1

IQN 2

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Datacore hints

• Special attention for software iSCSI

• Follow Datacore technical bulletin: TB15

ftp://support.datacore.com/psp/tech_bulletins/Tec

hBulletinsAll/TB15b_Citrix%20XenServer_config_501 .pdf

• Datacore in VM

• O.k. when not using HA

• Configuration possible, but take care about booting the whole environment

• Take care when updating XenServer

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StorageLink

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Logical advancement of XenServer integrated storage adapters

Netapp & Equalogic

Storage adapter

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Citrix StorageLink Overview (XenServer)

Guest

Snap-in for XenServer

XenServer

StorageLink

Data Path Control Path

iSCSI / FC

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Leveraging the best of virtualization and

storage

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StorageLink Overview

XenServer

Netapp ^EqualLogic VSM

Bridge

Hyper-V

VDS

SAN/NAS

Virtual Storage Manager

Parent Partition DOM0

XenServer

Data Path Data Path

Control Path

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StorageLink Gateway Overview

Vendor-specific VSM Storage Adapters run in separate processes

SMI-S is the preferred method of integration as it requires no custom

development work

Dell Dell

XenServer

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Storage Technologies

Storage Repository LUN

LVM Volume Group

LVM Logical Volume

VHD header VHD header

XenServer 5.5 iSCSI / FC

VM virtual disk

LUN

Storage Repository XenServer 5.5

iSCSI / FC +

LUN

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Snapshot types

XenServer (free) Essentials Enterprise Snapshot type Software based snapshot Hardware based snapshot