backup to zfs storage appliance best practices for exadata database machine

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. | 2

Backup to ZFS Storage Appliance Best Practices for Exadata Database Machine Emre Baransel Principal Advanced Support Engineer

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |

Using ESBU Oracle Engineered Systems Backup Utility for Oracle ZFS Storage Appliance

Which tasks are performed?

1. Oracle ZFS Storage Appliance configuration storage administrator

A project including NFS shares is configured in a user-selected storage pool.

2. Engineered System nodes configuration system administrator

The client NFS and Oracle Direct NFS (dNFS) are configured in this step.

3. RMAN run block script generation database administrator

RMAN scripts are generated in this step.

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http://www.oracle.com/technetwork/server-storage/sun-unified-storage/downloads/zfssa-plugins-1489830.html













Enable dNFS & configure oranfstab file

• What is dNFS? • How to enable/disable dNFS? • How to configure oranfstab file? • How to understand if dNFS is enabled? • How to understand if dNFS is being used? • How to monitor dNFS performance? • What about fstab options? • What about filesystemio_options?

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Instead of using the operating system kernel NFS client, you can configure Oracle Database to access NFS V3 servers directly using an Oracle Internal Direct NFS client, which is faster.




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$ cd $ORACLE_HOME/rdbms/lib

$ make -f ins_rdbms.mk dnfs_on

$ make -f ins_rdbms.mk dnfs_off

! Requires database restart



server: zfsserver1 NFS server Host name (Alias)

path: 10.177.52.158 First path to NFS server, NFS server NIC

local: 10.177.52.151 First client-side NIC

path: 10.177.52.159 Second path to NFS server, NFS server NIC

local: 10.177.52.151 Second client-side NIC (For load balance purpose)

export: /oraclenfs mount: /zfsbackup

| |mount point on a database server

|mount point on the NFS server


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DNFS searches for mount entries in the following order: 1. $ORACLE_HOME/dbs/oranfstab 2. /etc/oranfstab 3. /etc/mtab



Reported in the alert.log: ...

Oracle instance running with ODM: Oracle Direct NFS ODM Library Version 3.0

...

Direct NFS: channel id [0] path [celntap3-bc] to filer [celntap3-bc] via local [] is UP

Direct NFS: channel id [1] path [celntap3-bc] to filer [celntap3-bc] via local [] is UP


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- v$dnfs_servers

- v$dnfs_files

- v$dnfs_channels




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- v$dnfs_stats

NFS_READ: Read operations

NFS_WRITE: Write operations

- Performance Monitoring script here: Direct NFS monitoring and v$views (Doc ID 1495739.1)

- OS utilities sar,nmon.. can be used to monitor network traffic




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DNFS does not utilize NFS mount options. However setting the proper mount options is recommended to be in compliance with database requirements and to improve performance if DNFS is not operational and the system defaults to NFS. Oracle ZFS Storage: FAQ: Exadata RMAN Backup with The Oracle ZFS Storage Appliance (Doc ID 1354980.1) Sun ZFS Storage Appliance: Oracle Database 11g R2 NFS Mount Point Recommendations (Doc ID 1567137.1) Mount Options for Oracle files when used with NFS on NAS devices (Doc ID 359515.1)




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Direct NFS does not depend on the value of filesystemio_options. Direct NFS always issues async and direct I/O as it does not depend on OS support. However, since we can always fall back to the OS NFS client in case of mis-configuration, as a precaution, set filesystemio_options to 'directio' or 'setall' if the OS supports it.


Increase MTU size

• To avoid backup performance regression, the MTU size should be set to 65520.

• Backup/restore performance and stability will be higher on the higher MTU settings.

• The MTU size reduction should be utilized if page allocation failure events have been experienced

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Exadata version Recommended Permitted

< 11.2.3.3.0 or >= 12.1.2.1.0 65520 7000,15000,31000,64000

>= 11.2.3.3.0 and < 12.1.2.1.0 7000 15000,31000,64000,65520


Configure Projects To Use a Write Bias of “Throughput”

Synchronous writes are optimized for throughput. Data is written to the primary data disks instead of the log device(s), and the writes are performed in a way that optimizes for total bandwidth of the system.

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Increase "Database record size"

• 2013.1.1 or later code levels are required to use large 1MB record sizes.

• If the ZFS Storage Appliance is running earlier code, 128K record size is the largest available option.

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Backup Compression

• Attempting to compress data that doesn’t typically yield good compression results lengthens the backup window significantly, consumes unnecessary CPU resources, and results in very little space savings.

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Backup Type Duration Compression Ratio

nocompress 3 min. -

ZFS LZJB compression 2 min. 58% compression

ZFS GZIP compression 16 min. 75% compression

RMAN compression 16 min. 75% compression

A recent tablespace backup test results of Exa-ZFS configuration.


Keep some free space

• The recommendation from Oracle Exadata MAA and Sun ZFS Storage

Appliance development team is to keep 20% free space on each disk pool created, allowing the copy and write operations to run optimally. If the free space is allowed to reduce past the 20% recommendation, then write operations to the Sun ZFS Storage Appliance might be impacted because the appliance will be forced to spend more time looking for free space.

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ZFS-Exadata Configuration References

• Oracle ZFS Storage: FAQ: Exadata RMAN Backup with The Oracle ZFS Storage Appliance (Doc ID 1354980.1)

• Backup and Recovery Performance and Best Practices using Oracle Sun ZFS Storage Appliance and Oracle Exadata Database Machine

http://www.oracle.com/technetwork/database/features/availability/maa-wp-dbm-zfs-backup-1593252.pdf

• "Oracle Engineered Systems Backup Utility for Oracle ZFS Storage Appliance" tool http://www.oracle.com/technetwork/server-storage/sun-unified-storage/downloads/zfssa-plugins-1489830.html

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backup to zfs storage appliance best practices for exadata database machine

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