Designing a highly available database system involves taking various elements and combining them to suit your business needs and requirements. At the beginning of architecting a new high available Oracle database system it’s important to understand the need to make design and infrastructure decisions in the context of meeting Service Level Agreements (SLA). The SLA targets can be usually achieved… Read more
If you are trouble-shooting an AlwaysOn Availability Group topology, a study of the wait statistics will give a pointer to many of the causes of problems. Although several wait types are documented, there is nothing like practical experiment to familiarize yourself with new wait stats, and Joe Sack demonstrates a way of testing the sort of waits generated by an availability group under various circumstances.… Read more
Over the next few months, we'll be asking various well-known DBAs to describe their worst disaster caused by a mistake they made. To kick off the series, we asked Phil Factor to confess. He came up with a classic: The mistaken belief that a backup WITH CHECKSUM guaranteed a good backup that could be restored, and the ensuing disaster.… Read more
If you suffer from runaway queries, if you have several database applications with unpredictable fluctuation in workload, or if you need to ensure that workloads get the memory or CPU they need according to certain priorities, then you need Resource Governer, and you need Roy Ernest's clear explanation of the technology.… Read more
Having pierced the veil of confusion surrounding High Availability, Wesley David finds himself asked (and being asked) whether HA is worth the money it burns through. Perhaps it's more cost-effective to have a recovery process that moves like greased lightning?… Read more
Wesley has heard High Availablity touted as all sorts of technological cure-all for busy SysAdmins and DBAs, and now he's taking a stand against it. There are a range of things that High Availability is regularly confused with (either deliberately or innocently), and Wesley's clearing it all up.… Read more
