Archive for October, 2011
Posted October 26th, 2011
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Direct Path Read
By Eyal Markovich
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In previous posts, “db file sequential read” and “db file scattered read” wait events, I explained two common wait events that are associated with I/O Wait. In this post I will describe another common wait event that in many cases is caused by a weak storage performance.
Direct path read is an access path in which multiple Oracle blocks are read directly to the Oracle process memory without being read into the buffer cache in the Shared Global Area (SGA). This event is usually caused by scanning an entire table, index, table partition, or index partition during Parallel Query execution (although 11g support “direct path read” on serial scans). The following SQL statement illustrates a parallel query scanning a table:
| Sample SQL Query:Select /*+ Parallel(emp 4) */ * from Employee emp;
Execution Plan:
SELECT STATEMENT
PX COORDINATOR
PX RECEIVE
PX SEND RANGE
PX BLOCK ITERATOR
TABLE ACCESS FULL EMPLOYEE |
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Tags:direct path read, I/O wait, index, index partition, IOPS, Kaminario, Oracle, Oraclee process memory, parallel queries, parallel query execution, reads, Shared Global Area, SQL statement, storage latency, Storage Performance, table partition, throughput, wait events, writes
Posted in Oracle Database Performance | No Comments »
Posted October 20th, 2011
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Databases Dissected
GEORGE CRUMP TAKES ORACLE DATABASES APART AND TELLS YOU WHAT TO DO WITH EACH COMPONENT.
By Gareth Taube, Vice President Marketing, Kaminario
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Few writers can dissect and illuminate a data storage issue better than George Crump, author of the well respected Storage Switzerlandblog. If you really want to understand the nuts and bolts of database performance and storage requirements, take a close look at his latest entry entitled Choice is Critical When Selecting Oracle SSD.
George takes the reader past the issue of which applications makes sense for DRAM and which make sense for Flash, a topic you have no doubt read about in many places. Instead he takes a fine scalpel to Oracle databases, dissecting them into their many components—the Oracle data file, Redo files, Undo tablespaces, and Temporary tables–and assembles a viable strategy for applying SSD types to each these components for maximum performance.
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Tags:data storage, databases, DRAM, enteprise level, Flash, K2-H, Kaminario, Oracle, Oracle data file, Oracle redo file, SSD, temporary tables, undo tablespaces
Posted in Oracle Database Performance | No Comments »
Posted October 19th, 2011
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Kaminario at SNW, Oracle Openworld, and SQLPASS Summit
By Gareth Taube, Vice President Marketing, Kaminario
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Kaminario debuted its new K2 all solid-state SAN storage solutions at Storage Networking World (SNW), Oracle OpenWorld, and the SQLPASS Summit. The converstations that we had with application developers at these shows reinforced the need for high performance, highly available all solid-state SAN storge that meets their application performance requirements and budgets. Check out the videos from SNW and Oracle OpenWorld at http://www.kaminario.com/Resources/Videos/.
Tags:DRAM, Flash, Kaminario, Oracle, Oracle OpenWorld, solid-state SAN storage, SQL Server, SQLPASS Summit, SSD, Storage Networking World
Posted in Oracle Database Performance | No Comments »
Posted October 14th, 2011
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SSD Sprawl: Don’t Worry. Be Happy
NOTHING BEATS SAN-BASED SSD FOR EFFICIENCY AND HIGH UTILIZATION.
By Gareth Taube, Vice President Marketing, Kaminario
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A September 21, 2011 IBM/Zogby International study shows a lot of pent up demand for solid state drives (SSD). Nearly half (43 percent) of IT decision makers surveyed said they were already using SSD or had plans to use it in the future and 75 percent said that speeding delivery of data was the motivation for using SSD technology. According to IBM’s press release, “Customers are embracing high-performance solid-state disks to support growing data storage demands driven by cloud computing and analytics technologies.”
Interesting results, but perhaps even more interesting is the press coverage that is already warning IT about the dangers of SSD sprawl, similar to the server, virtual machine, and hard disk sprawl IT departments wrestled with in the past. In fact, Storage Soup, a SearchStorage.com blog has an entry entitled Are You Ready for SSD Sprawl?
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Tags:DRAM, Flash, IBM, IT, IT decision makers, K2, K2-H, Kaminario, PCI, SAN, server sprawl, SPEAR operating system, SSD, SSD sprawl, Zogby International
Posted in SSD Architectures | No Comments »
Posted October 7th, 2011
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Free at Last
FREEDOM MEANS THE BEST MIX OF DRAM AND FLASH
By Gareth Taube, Vice President Marketing, Kaminario
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Why are we making such a big deal about freedom of choice in the K2-H hybrid solution? Because it means you can achieve just the right mix of Flash and DRAM in a single Kaminario K2-H unit to yield the best cost/performance ratio for your applications.
DRAM yields the absolute fastest performance and lowest latency for both application random reads and writes, but it’s also the most expensive of the SSD memory types. Flash is considerably less expensive, but application writes are much slower with Flash than with DRAM because Flash has to erase data in memory first before anything new can be written to it. Your goal should therefore be to use expensive DRAM only where it is absolutely needed and leave the rest to the less expensive Flash. The K2-H lets you do just that, installing different mixes of DRAM and Flash in the same unit to achieve just the right mix for your application needs.
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Tags:analytics, business intelligence, DRAM, Flash, IOPS, K2H, Kaminario, Microsoft, OLTP, Online Transaction Processing, Oracle, Oracle RAC, performance, reads, Redo files, SQL Server, SSD, tablespaces, writes
Posted in Hybrid Storage | No Comments »
Posted October 2nd, 2011
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Accelerating Oracle Real Application Clusters (RAC) Performance
By Kaminario
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Enterprises in every industry rely on fast access and processing of business critical information stored in their databases to stay competitive and grow their business. Companies around the world rely on Oracle databases for their most demanding and critical applications. This white paper talks about how Oracle RAC and Kaminario K2 all solid-state SAN storage solutions deliver clustered high performance, scalability and reliability. Download white paper now.
Tags:Database Performance, Kaminario K2, Oracle, Oracle Real-time Application Clusters, RAC
Posted in Oracle Database Performance | No Comments »
