Archive for January, 2008
Tuesday, January 22nd, 2008
I/O stack components Overview
Typically the stack consists of the following
• Database
• Character or block device driver
• Multipathing driver
• SCSI driver
• HBA
• System Bus
• Switch/iSCSI routers
• Storage Array
• Disks
Example of vendors:
ASM-Database IBM Oracle
Character or block device driver
Multipathing driver – PowerPath, Windows MPIO
SCSI driver
HBA – Host Bus Adapter, Qlogic (IBM), Emulex
System Bus ...
Posted in hardware setup, oracle, ibm db2, Back-of-the-Envelope, Database, Storage, Design, Fibre Channel, Capacity planning | No Comments »
Tuesday, January 22nd, 2008
Don't forget to add extra IO imposed by users of the database. For example, to determine how much extra I/O will be imposed on the system when the new load is put into place. For example, if more users or reports will be added, determine how much I/O these reports ...
Posted in oracle, Back-of-the-Envelope, Storage, Design, Capacity planning | No Comments »
Tuesday, January 22nd, 2008
IO rate of 1+ Gigabytes/sec is rarely achievable, but hundreds of Megabytes/sec is achieved in lots of high-end production environment. Keep those numbers in mind when planning for what's possible.
In Oracle, use AWR reports to determine current I/O metrics (Instance Activity Stats per sec).
• IOPS = “physical reads total I/O ...
Posted in oracle, Back-of-the-Envelope, Database, Design, Capacity planning | No Comments »
Tuesday, January 22nd, 2008
Common misunderstandings:
“If I buy 2 Gigabit HBAs I will get 2 Gigabytes of throughput, that’s more than enough throughput for my 400 MB/s application”
“I only need 2 disks to store my 1 TB database, now that we have 500GB disk drives are available!”
The first misunderstanding is not just about bits ...
Posted in Back-of-the-Envelope, Database, Storage, Design, Fibre Channel, Capacity planning | No Comments »
Tuesday, January 22nd, 2008
IOPS
• The standard unit of measurement for I/O operations per second.
Includes all reads and writes.
• This is how you rate a I/O stack components ability to process small
block random I/O requests.
• Used to describe I/O rate driven applications (OLTP, random I/O )
Mbytes/s
• Mega”Bytes” per sec
• Used to measure large block ...
Posted in oracle, Back-of-the-Envelope, Database, Storage, Design | No Comments »
Tuesday, January 22nd, 2008
Saw this definition from one of the Oracle OpenWorld sessions, thought it was pretty clear and concise:
Throughput
The measure of the transfer of bits across the media over a given period of time. Commonly used in discussing data transfer rates
Due to a number of factors, throughput usually does not match the ...
Posted in Back-of-the-Envelope, Database, Storage, Design, Fibre Channel | No Comments »
Thursday, January 10th, 2008
When you have a performance concern, check the operating system settings to determine if these settings are appropriate for your application. Because the Linux operating system is not a WebSphere Application Server product, be aware that it can change and results can vary.
Procedure
Configure the following settings and variables according to ...
Posted in app server tuning, hardware setup, linux, file systems, websphere 6.0.x | No Comments »
Thursday, January 10th, 2008
IBM describes how to tune Windows 2000, Windows XP, and Windows 2003 operating systems to optimize the performance of WebSphere Application Server. Because Windows operating systems are not WebSphere Application Server products, be aware that the products can change and results can vary.
Procedure
Configure the following settings or variables according to ...
Posted in windows, websphere 6.0.x | No Comments »
Thursday, January 10th, 2008
IBM recommends a number of configuration changes and variables you can set to tune the performance of Websphere to suit your needs. Because the AIX operating system is not a WebSphere Application Server product, be aware that it can change and results can vary.
Procedure
Change the following configuration settings or variables ...
Posted in os tuning, performance monitoring, aix, file systems, websphere 6.0.x | No Comments »