© 2004 hewlett-packard development company, l.p. the information contained herein is subject to...

© 2004 Hewlett-Packard Development Company, L.P.The information contained herein is subject to change without notice

Volume Concepts

HP Restricted

Module 5

Sept 2004 HP Restricted 2

Objectives• Describe basic RAID theory• Describe the concepts of XP Parity Group and Free Space

as they apply to drives with RAID theory• Describe how Free Space is used in the XP array, including

a discussion of emulation type and fixed volume creation• Describe the various XP array volume types including

normal, custom, and expanded, including the process to create each type

• Describe how XP volumes are made available for use by mapping a volume to a port

• Describe the difference between an LDEV, a volume, and a LUN

• Describe OPEN-V volume details and functionality, including benefits and implementation mechanisms


A solution

RAID

• Provides for highly available data despite a disk failure

• Provides for online reconstruction of lost data

• Costs space

• Industry-standard redundancy algorithms


XP array Parity Group (1 of 2)

(A RAID group)

XP marketing array group

RAID control

XP array Parity Group

Protected data

From an array group of independent disks to an XP array Parity Group

Unprotected data

(A group of disks)


XP array Parity Group (2 of 2)

RAID protected available space

• Usable space

• Free Space

• How is Free Space created?

XP array Parity Group

Protected data

(A RAID group)


The four steps to using Free Space

1. Define an emulation type for the Parity Group

2. Assign volume information

3. Map the volumes to a CHIP port

4. Connect the server


Emulation types and normal volumes

• Predefined (virtual) drive size

• Defined for at the Parity Group level

• Defining an emulation type creates a volume

• Normal volumes are fixed in size

• Open systems have OPEN-* emulation types


Applying an emulation type

Assign an emulation type to the Parity Group

Parity Group

Free space

Emulation type defined

OPEN-E

OPEN-E

OPEN-E

OPEN-E

Free space

OPEN-E

Define

emulation

type

OPEN-E


Creating volumes

Exercise

Creating volumes from Free Space

Problem

• A Parity Group with 32GB Free Space

• An emulation type with a fixed size of 3.0GB

Questions

After setting the emulation type

• How many normal volumes are created?

• How much Free Space is left?


Volume designation

The unique CU:LDEV number identifying the logical storage device

• CU is control unit

• LDEV is a logical device within a control unit

• The CU and the LDEV number uniquely identify a virtual XP array disk or volume

Example

For volume 01:2a CU=01, LDEV=2a


XP array volumes

In the XP array a volume refers to the CU:LDEV number

• The CU number is used by the XP internal data structures to manage virtual disks

• One CU number can contain 256 LDEVs

• The LDEV number is an arbitrary number from 0 – FF

• Together, the CU and the LDEV number uniquely identify a virtual XP Array disk called a volume

Example

CU=1 and LDEV=2a, the volume = 1:2a


Assigning volume information

• After specifying an emulation type for a Parity Group, assign numbers to the OPEN-E volumes

• The volume number uniquely identifies the virtual disk

Emulation type defined

OPEN-E

OPEN-E

OPEN-E

OPEN-E

Free Space

OPEN-E

Volume assignments

00:00

01:0001:01

Free Space02:01

Assign

volume

numbers

OPEN-E

02:00

OPEN-E


Array configuration — addressing

Hardware XP12000Number Of CUs 64

Number of volumes/subsystem Maximum 16384 (64CU x 256LDEV)

Emulation type OPEN-3/8/9/E/L/V, CVS, LUSE

Number of LUNs/path 1024


Solution: Banding (ZBR)

Outer Band

Inner Band

12 Sectors Per Track

6 Sectors Per Track


Disk zones of a 72GB 15k rpm drive

ldev performace on a single Raid Group

150.0

160.0

170.0

180.0

190.0

ldev1

/2

ldev3

/4

ldev5

/6

ldev7

/8

ldev9

/10

ldev1

1/12

ldev1

3/14

ldev1

5/16

MB

/s

outer zone

middle zone inner

zone

Thruput differenc outer disk zone to inner disk zone

0.0%

20.0%

40.0%

60.0%

80.0%

100.0%

read write

outer zone inner zone

For sequential I/O loads a noticeable performance difference of about 20% between outer and inner tracks can be observed

Comparing the performance of the ldevs across the drive surface it appears that there are three zones on the disk

Thruput difference outer disk zone to inner disk zone

0.0

50.0

100.0

150.0

200.0

read write

MB

/s

outer zone inner zone


Data Placement on Drive

Outer tracks have a higher transfer rate than inner tracks

Preferably place sequential work areas on the outer tracks if performance needs to be optimized (e.g. Redo Logs)

In standard configurations the outer ldevs have the lower ldev numbers in the array group

The latency (affects random access) depends on the rotational speed and therefore is the same on the inner and outer tracks


LUN mapping (mapping volumes)

• Volume mapping

• Mapping a volume to one or more CHIP ports

• Alternate paths

• How to uniquely identify the XP disk seen by server?


Volume types

• Normal volumes have a fixed size

• Custom volumes have a smaller CVS

• LUSE volumes are groupings of identical volumes to produce an extended volume


Creating different volume types

Logical unit creation and sizes

Fixedsize LU(normal volume)

Smallsize LU(CVS volume)

Largesize LU(LUSE volume)

OPEN-3(2.4GB)

OPEN-3(2.4GB)

OPEN-3(2.4GB)

LU

LU

LU

CVS(1.2GB)

CVS(1.2GB)

CVS(1.2GB)

CVS(1.2GB) LUSE


CVS

• Smaller sized volumes

• CVS are created from Free Space or from LDEVs that have been added to the free space

• Used for XP command devices


LUSE

• Licensed functionality to create expanded volumes

• Volumes must be similar (same CU, size, RAID type, and emulation)

OPEN-9 * 1 Volume 0:02


OPEN-9 * 3

OPEN-9 * 1




LUSE functional description

LUSE combines two or more LDEVs to function as one large LDEV

(01:00)

(01:01)

(01:03)

(01:04)

(01:05)

LUSE (01:00)


OPEN-V overview

OPEN-V is a virtual emulation

• A process and an emulation

• Easily provides a custom volume size

• Extension/combination of CVS and LUSE functionality

• Volume sizes from 46.8MB to 2TB

• Volume size is specified in either MB or cylinders orthe number of volumes to create


OPEN-V creation

LU creation with OPEN-V

Flexible size LU

FreeSpace

Specify

capacity

LU

LU

LU


Basic specifications

Items Specification

Specified unit MB or cylinder

Capacity (GB/)vol 46.8MB to 2TB

RAID level RAID5 and RAID1

Drives supported All

Inquiry production ID OPEN-V

OPEN-V*n (volume over 62GB)

OPEN-V-CM or

OPEN-V*n-CM (command device)

(n = maximum 36)

Supported platform(at initial release)

Solaris, HP-UX, AIX, Windows NT, Windows 2000


Function support

Functions Contents

CVS Open-V includes CVS capability

LUSE Support

Cache LUN Support

CA Support(Pair volume must also be OPEN-V)

BC Support(Pair volume must both be OPEN-V)

AutoLun Support(Source/target volumes must both be OPEN-V)

Data exchange oto Support

Data exchange mto, otm Not supported


Ways to create OPEN-V volumes

OPEN-V volumes can be created three ways

• Specify volume size and number of volumes

• Specify number of volumes

• Specify the size of the volumes


Initial volume creation method 1

Specify the volume size and number of volumes

ExampleSize = 40GBNumber = 2

Parity Group(VDEV)

Free Space

OPEN-V(40GB)

OPEN-V(40GB)

FreeSpace



Specify the number of volumes

ExampleNumber = 4

Parity Group(VDEV)

FreeSpace

OPEN-V

OPEN-V

OPEN-V

OPEN-V



Specify the size of the volumes

Example Size = 10GB

Parity Group(VDEV)

FreeSpace

OPEN-V

OPEN-VOPEN-V

OPEN-V

OPEN-V

Free Space


OPEN-V volume addition

Specify volume size and number of volumes

ExampleSize = 3GBNumber = 2

Parity Group(VDEV)

OPEN-V(3GB)

OPEN-V(40GB)

OPEN-V(40GB)

Free Space OPEN-VOPEN-V

OPEN-V(40GB)

OPEN-V(40GB)

Free Space


Internal mechanism (OPEN-V greater than 62GB)

Internal CVS and LUSE procedures

Create OPEN-Vvolume size = 100GB

Parity Group(VDEV)

CreateOPEN-V

CVS

LUSE

User view

FreeSpace

Free Space

OPEN-V*2(100GB)

OPEN-V(50GB)

OPEN-V(50GB)

Free Space


Learningcheck


Labactivity

© 2004 hewlett-packard development company, l.p. the information contained herein is subject to...

Documents

xp array volumes

raid group slide

xp volumes

concepts of xp parity

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various xp array volume

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