Extreme availability with Oracle stretched clusters

Bart Sjerps Oracle, VPLEX

Some of my customers have been pushing for more availability in their Oracle database applications. They want to eliminate downtime completely even if they experience a site failure. Whether this is a real business requirement or a technology push, I’m not sure – I guess a bit of both.

ha_aircraft

Most of these customers have already implemented Oracle RAC (Real Application Clusters), which provides them active/active server clustering for Oracle. If one of the servers in a RAC cluster fails, the others just keep running – no restart or recovery involved. This is a High Availability option typically for local sites.

For Disaster Recovery, most customers have some sort of storage replication (i.e. EMC SRDF/Synchronous or SRDF/Async, or they use Oracle Data Guard for this which replicates data on the Oracle database level). This protects against site failures and offers zero or near-zero dataloss (for committed transactions in Oracle – the non-committed transactions are rolled back during the restart – and this is exactly one of the problems by the way).
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Why use Oracle ASM for Oracle databases

Bart Sjerps Oracle

I’ve been in discussions with some customers recently about what is the best way to store Oracle database data. Needless to say that the foundation should be EMC infrastructure of course, but apart from that, what kind of volume manager and/or filesystem works best for performance and other features?

There are many volume managers, and many filesystems available, more or less dependent on what hardware and operating system you run the database.

Some have a long track record, some are new kids on the block. Some are part of the operating system, others are 3rd party add-ons, for which you might need to pay licenses.

One way of storing Oracle database data is Oracle ASM.
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Managing database performance SLA’s with quality of service

Bart Sjerps Oracle, Performance

A guy walks into the showroom of a Porsche dealer. He wants to buy a new set of hot wheels. The sales guy tells him about the latest technology in sports car design. This year’s model has active 4-wheel drive traction control, a very powerful engine (over 500 horsepower) with direct fuel injection, semi-automatic dual-clutch with seven speeds, and the whole car is weight-balanced to offer the best handling and cornering speeds. At the same time, carbon emissions per kilometer are the lowest in years and the car actually has green labels, so at least you can make yourself believe that it does not ruin the environment too much 😉

Porsche

“Great,” says the customer. “What’s the acceleration and top speed?”

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Thin Provisioning

Bart Sjerps General, Oracle

Some customers ask us – not surprisingly – how they can reduce their total cost of ownership in their information infrastructure even more. In response, I sometimes ask them what the utilization is of their storage systems.

Their answer: often something like 70% – you need of course some spare capacity for sudden application growth, so close to 100% is probably not a good idea.

Overallocating storage
Overallocating storage

If you really measure the utilization you often find other numbers. And I don’t mean the overhead of RAID, replication, spare drives, backup copies etc. because I consider these as required technology – invisible from the applications but needed for protection and so on. So the question is – of each net gigabyte of storage, how much is actually used by all applications?

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