Backup Options for IBM PureData System for Analytics, powered by Netezza

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March 31 is [World Backup Day]!

Recently, a client asked how to backup their IBM PureData System for Analytics devices. IBM had [acquired Netezza in November 2010], and later renamed their TwinFin devices as the IBM PureData for Analytics, powered by Netezza.

The [IBM PureData System for Analytics] is incredibly fast for performing deep, ad-hoc analytics. However, the people who use them are "data scientists", not backup experts.

Likewise, there are backup administrators who may not be familiar with the unique characteristics of this expert-integrated system to know what backup options are available.

As with the rest of the IBM PureSystems line, the IBM PureData System for Analytics (or, PDA for short) has a combination of servers, storage and switches inside.

In a full-frame PDA, there are two servers in Active/Passive mode, these coordinate activity to FPGA-based blade servers, which have parallel access to hundreds of disk drives, storing nearly 200 TB of compressed database data. A system can span up to four frames.

But what do you backup? And why? You don't need to worry about backing up the Linux operating system or NPS server code, that is considered firmware and if anything every got corrupted, IBM would help restore it for you. System-wide metadata, such as the host catalog and global users, groups, and permissions should be backed up periodically to protect against data corruption.

There are a number of reasons to backup your user databases:

• As part of firmware upgrade/downgrade
• To transfer data to another system
• Protect against hardware failure / disaster
• Protect against data corruption

The PDA has three backup formats. You can backup the entire user database in compressed format, backup individual tables in compressed format, or export to a text-format file.

Compressed format is faster, but can only be restored to the same PDA, or a PDA that has the same or higher level of NPS firmware. The text-format is slower, but can be used to restore to lower levels of NPS firmware, or to other database systems.

There are basically two methods to backup your PDA. The first is called the "Filesystem" method. Basically, you can attach an external storage device to the NPS server, and use the built-in command line interface (CLI) to store the backups onto its file system.

nzhostbackup

On NPS version 6, the nzhostbackup will backup the /nz/data directory which stores the system tables, database catalogs, configuration files, query plans, and cached executable code for the SPU blade servers.

(I have heard that the nzhostbackup will get deprecated in NPS version 7, but I only have access to version 6. As always, [RTFM] for your specific NPS code level.)

nzbackup -users

The nzbackup with the users parameter will backup the global users, groups and permissions. This is included in the /nz/data backup contents from the nzhostbackup command, but you may want to backup and restore these separately.

nzbackup -db

The nzbackup with the db parameter will backup a user database in compressed format. To backup individual tables, use the CREATE EXTERNAL TABLE command, which can create compressed or text-format exports.

You may find that your databases are so large, they will exceed the limits of the filesystem on the external storage device. For SAN or NAS deployments, I recommend the IBM Storwize V7000 Unified with IBM General Parallel File System (GPFS). However, if you are using something else, you may need to use the "nz_backup" scripts provided which split up the backup images into smaller pieces that most other filesystems can handle.

The PDA comes with 10GbE Ethernet ports that you can attach a NAS storage device over a Local Area Network (LAN), or add Fibre Channel Protocol (FCP) ports and connect over a Storage Area Network (SAN). To keep things simple, I will refer to whichever network you decide as the "Backup Network" in the drawings.

The second method for backup is called the "External Backup Software" method. As you have probably guessed, it involves sending the backups to a supported software product like IBM Tivoli Storage Manager (or, TSM for short).

In this case, the PDA acts as a client node, similar to a laptop, desktop, or application server with internal disk. Backup data is sent over the LAN to the designated TSM server, and the TSM server in turn writes over the SAN to its storage hierarchy of disk, virtual tape and/or physical tape resources.

Backups can be done by command "on demand", or automated on a schedule. For the /nz/data directory, direct the nzhostbackup command to send the backup copy to local disk, then use TSM's dsmc archive command to transfer this backup copy to the TSM server.

For nzbackup with the users or db parameters, you can send the data directly to the appropriate TSM server by specifying the connector and connectorArgs parameters.

To reduce traffic on the TSM Server, an intermediary "TSM Proxy Node" can be put in between. In this case, the PDA sends the backup to the Proxy Node, the Proxy Node uses a "LAN Free Storage Agent" to send the backups directly to the virtual tape and/or physical tape, and then notifies the TSM Server to updates its system catalog to record which tape holds these new backups.

Another configuration involves installing the TSM LAN Free storage agent directly on the PDA. While this will require FCP ports to be added and consume more CPU resources on the NPS server, it eliminates most of the LAN traffic, allowing the PDA to send its backups directly to virtual or physical tape.

To learn more about this, see my full presentation [Backup Options: IBM PureData System for Analytics, powered by Netezza] on the IBM Expert Network powered by SlideShare, or attend the upcoming [IBM Edge 2014] conference in Las Vegas, May 19-23. I will be there!

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