Optimizing ORACLE through Storage

Virtualization

Matt MillerProduct Marketing Mgr

VERITAS Software

Agenda

Demands of today’s applications Storage Virtualization Defined Improving Manageability Enhancing Performance Meeting Availability

Requirements

Optimizing Oracle Helps administrators meet the demands

of today’s business applications:

– Performance requirements - 70% of e-business users will leave if no response in 15 seconds

– Manageability requirements - exponential data growth while IT resources scarce

– Availability requirements - today’s businesses operate 24 x 365

Everyone wants to talk aboutStorage Virtualization What is it?

– Coordinated control and management of aggregates of online storage devices to produce some beneficial effect

• Beneficial effects• Resiliency • Utilization • Performance

It’s about managing storage resources effectively

Two Old Terms Applied to a New Model ConsumerConsumerConsumer

Storage Resources

Provisioning …give users the right amount, of

the right kind, accessible at the right time

Virtualization …using these

across the entire data center

Storage consolidation enables the delivery of a set of tools to support data center-wide management

Storage Virtualization• Makes physical disks…

• Fixed size• Bounded performance• Do break (occasionally)

• …into “virtual disks”• As big as you need • As fast as you need • Very “reliable” • New capabilities (e.g., can grow)

virtualization

Heterogeneous storage devices

Storage Virtualization Layer

Highly availableVirtual disk

High capacity virtual disk

Applications

Not Exactly New…

Disks

+

Packaging & integration+

Processors & software

“virtual disks”…aka RAID

RAID: Managing Resources for Beneficial Effect

                    

stripe

big, fast, risky

mirror

big, very safe, fast, expensive

RAID 5

big, sort of safe, fast, cheap

“virtual disk”

whatever size, speed, reliability users need

host

Life Is Good…• Storage Virtualization helps Oracle:

• Have any size “disk” it needs • Increase performance by adding disks • Be protected against hardware failures

• Disk• Controller • etc….

• Store data on “disks” that can grow when more storage is required

• “Freeze” disk contents for backup etc. • Recover quickly from logical errors

…and the Market Proves it

All enterprise disk subsystems available today use RAID technology to virtualize

storage

Innovators

intro growth maturity replacement

X

Disk subsystemvirtualization

time

adoption

Mainstream

Early Adopters

Improving Manageability through Improving Manageability through Storage VirtualizationStorage Virtualization

Business Benefits #1) Lower hardware costs

– Maximization of current hardware resources– Hardware Independence

#2) Greater IT productivity– Simplified administration of heterogeneous environments – Proactive management of applications

#3) Increased application ROI– Improved throughput– Increased uptime “on-line everything”

Lower Hardware Costs• FACT:FACT:

Less than 50% of UNIX/Windows Less than 50% of UNIX/Windows disk is utilizeddisk is utilized

• SOLUTION:SOLUTION:Allow dynamic (re)sizing and Allow dynamic (re)sizing and logical space allocationlogical space allocation

Example: Example:

““Logical” pools across Logical” pools across heterogeneous storage subsystems heterogeneous storage subsystems

Extent based file allocation lessens Extent based file allocation lessens fragmentation to increase fragmentation to increase performanceperformance

Lower Hardware Costs• FACT:FACT:

Homogeneous solutions “trap” Homogeneous solutions “trap” enterprises into expensive, enterprises into expensive, proprietary architectures proprietary architectures

• SOLUTION:SOLUTION:Provide a consistent approach to Provide a consistent approach to heterogeneous environments – the heterogeneous environments – the net/net equates to flexibility of net/net equates to flexibility of choicechoice

Greater IT Productivity• FACT:FACT:

Most System and Database Most System and Database administrators spend an increasing administrators spend an increasing amount of time managing an amount of time managing an environment growing in complexity environment growing in complexity

• SOLUTION:SOLUTION:Automate manual tasksAutomate manual tasks

• Example: Example: Dynamic sizing of volumes and file Dynamic sizing of volumes and file

systems systems ““On the fly” performance tuning On the fly” performance tuning

Greater IT Productivity• FACT:FACT:

It costs more to manage 10 GB It costs more to manage 10 GB of disk than it does to purchase of disk than it does to purchase itit

• SOLUTION:SOLUTION:PProvide the benefits of rovide the benefits of “proprietary commodity” “proprietary commodity” systems without the associated systems without the associated costscosts

Example: Example: FlashSnapFlashSnap

DMP DMP

Increased Application ROI• FACT:FACT:

Planned downtime and un-planned Planned downtime and un-planned downtime affect application downtime affect application availability – which equates to lost availability – which equates to lost revenuerevenue

• SOLUTION:SOLUTION:Decrease the need for “planned Decrease the need for “planned downtime”downtime”

• Example:Example: Dynamic RAID reconfiguration Dynamic RAID reconfiguration Online file expansion & defragmentationOnline file expansion & defragmentation

Off-host Processing

Oracle OracleMirror

Take SnapshotBreak off Mirror from

Primary

Import Disk Groupfor Processing on Secondary

Off-host Processing with Oracle Offline Backup

– Oracle not accessible during snapshot creation– Snapshot imported to alternate host– Production environment protected from backup

overhead

Online Backup– Oracle placed into “hot backup” mode while

creating snapshots– Once created, Oracle taken out of HB mode– Again, backup overhead is avoided on production

server

Off-host Processing with Oracle Create a secondary Oracle database

– Create volume snapshot– Import to alternate host with Oracle installed– Use the secondary DB for operations such as

loading DWs, DSS, and application testing

Example of volume snapshot technology in Oracle environments

– VERITAS FlashSnap– Tested in accordance with the Oracle Storage

Compatibility Program (OSCP)– http://www.oracle.com/ip/deploy/database/storage/index.html?vendors.html

Enhancing Performance

Enhanced Performance

Performance can be everything

– Elegant designs can fail in production because of performance problems

– Administrators spend hours monitoring and balancing I/O loads to achieve better performance

Enhanced Performance Increased performance = increased

productivity– Equal to raw device performance

Large I/O optimization– Accelerated I/O performance for large files (e.g., video,

images)

Creating logical volumes of physical disks can balance I/O loads

– Through data striping

Oracle9i Oracle Disk Manager ODM API developed by Oracle for Oracle9i

ODM offers simplified management framework for Oracle

Requires an enterprise File System with the API “glue”

– VERITAS File System– NetApp DAFS solution

ODM Key Messages ODM is Oracle’s idea

– It is how Oracle wants to do I/O– Oracle encourages customers to use filesystem files

ODM is not just an I/O performance package

ODM supports raw partitions mostly to reduce the pains of a migration

Usage of ODM today will not hinder Real Application Clusters deployment in the future

Oracle Disk Manager Features Support for File System I/O

– Raw performance or better for file systems – Single system call for all I/O types– Supported on both raw and file system files

File Management– Contiguous disk space allocation– Simplified file creation– Supports Oracle Autoextend

File Identification– Reduced CPU overhead

ODM File I/O

Oracle without ODM– Without ODM, Oracle must resort to many different sets of calls to

provide the wide variety of IO types. Example: pwrite()/pread(),async_write(),readv(),read(),write() lio_listio(),kaio()

– Without ODM, asynchronous DBWR page flushing requires two calls: one to issue the I/O and another to poll for completed IO

Oracle with ODM– With ODM, Oracle needs only a single call

odm_io()­odm_io() supports ALL Oracle file IO types on ALL files

(Raw or VxFS)! Gathered writes (DBWR) and LGWR asynchronous

writes occur with a single call to odm_io() without regard for file type (VxFS or RAW) or number of target files

ODM File Creation Features ODM Includes features that enable more effective Oracle file

creation Without ODM, failed attempts to add files to a database will

result in an unused file to be cleaned up from outside Oracle. With ODM, files are no longer created with traditional open()

or create()– Files will be created with odm_create() and then initialized or filled.

If Oracle is happy with the file it calls odm_commit() If Oracle is not happy with the file, Oracle calls odm_abort(). The

file will be completely cleaned up from within ODM.

With ODM, VxFS files are laid out with contiguous disk blocks. – This aids table and index scan throughput

File Resizing Features

ODM supports Oracle’s autoextend by adding contiguous disk blocks to a tablespace

– However, there will most likely be a hole between the old datafile and the extents added with the odm_resize() command

This is not adding a datafile, but instead just adding extents to the existing datafile

– Oracle cannot autoextend a raw partition unless it is a VxVM volume

– On UFS, the added portion will not be contiguous

File Identification Feature Large databases require too many kernel resources

– Most notably per-process and system-wide file descriptor slots

With Oracle Dedicated Processes (Shadow Processes), large numbers of users combined with large numbers of datafiles becomes an issue.

– Example: 1000 users on 500 datafiles will cost 500,000 kernel file descriptor table entries

Kernel file descriptor usage is protected with locking. Performing a high rate of implicit/explicit file open/close operations will cause undesirable amount of kernel-mode CPU cycle wastage.

– File open/close internals use the same kernel locking infrastructure.

File Identification Feature (cont) With ODM, Oracle no longer uses file descriptors. Instead,

ODM Identifiers are used.

ODM Identifiers are shareable from process to process within the node

Oracle caches ODM Identifiers in the SGA at instance startup– DBWR performs initial odm_identify() on all datafiles– CKPT identifies the control files and caches the information– LGWR is responsible for the initial identify and caching for REDO logfiles

ODM Identifier usage reduces Kernel overhead– Calls to exec(),and exit() no longer cause implicit contention on Kernel file

descriptor locks– Explicit contention is eliminated ( open() / close() )

Meeting Availability RequirementsMeeting Availability Requirements

Faster Recoverability

On-disk recovery of Oracle

– Simple

– Fast

– Granular

– No disruption to production databases

– Useful for any application requiring a stable image

Recoverability:Storage Checkpoint A point-in-time image of file system

Maintains changed data blocks as database is being updated

Mountable: Read-only or R/W– All file system functions can be performed

Storage Checkpoint: A Simple Example When a Storage Checkpoint is first

taken:/oradata

A

B

H

G

D

C

E

F

No data is copied to the Storage Checkpoint

Takes a couple of seconds

Presents the point-in-time image of /oradata by finding data from the primary file system, /oradata

Storage Checkpoint

A Data Storage Checkpoint:As the /oradata changes

/oradata

A

B

H

G

D

C

E

F

Copy-on-write mechanism first copies the before-image to the Storage Checkpoint and then updates the data block in the primary file system

Mountable and writable

Copy-on-write in place until the next Storage Checkpoint created or the Checkpoint is removed

A’

G’

Storage Checkpoint

A

G

Storage Checkpoint Applications Storage Rollback

– On disk recovery

Block-level incremental backups– Decrease or eliminate backup windows for

Oracle

Database Clones– Allows the database to be queried while loading

Storage Rollback

Storage Checkpoints are simply on-disk backup images

– Consistent, stable images of a file system at a particular point in time

Storage Rollback is “restore” from the on-disk backup or Storage Checkpoints

– Copies before-images of data blocks back to the primary file system (block-level restore)

– Storage Rollback is not a database recovery operation

– DBAs must follow database recovery steps

Standard Database Recovery

fsck processing

Restore from backup

Reapply transactions 00:00 - 15:00 - Back in service

12:00 24:00

15:00

Full DBBackup

Transactions

Time0:00

Storage Rollback

10:00 12:00 14:00 24:00

15:00

Restore from last checkpoint

Reapply transactions 14:00 - 15:00 - Back in service - fast

Full DBBackup

Transactions

Storage Checkpoints - on-disk, storage efficient backup images

Time0:00

Summing Up Virtualization enables storage-centric

– Data centers – Enterprises

Makes IT sense: data is the valuable asset– Over half of corporate data resides in DBs– 80% by 2003– Oracle #1 in worldwide DB market

Networked storage introduces new complexities – Dozens of non-cooperating servers connected to– Thousands of heterogeneous storage devices – Applications can suffer as a result

Summing Up The only way to cope with the complexity

– Enterprise-wide storage administration Virtualization

– Practiced for a decade – Evolving: RAID boxdata centerenterprise

Provisioning – Easy with direct-attached storage– A complex SAN challenge currently being addressed

Give Oracle the right:– Amount of storage at– the right time with– the right type and performance

Thank You!