Only one reply...Cheers Alan, which was.......
Vendors typically measure maximum I/O rates in a way that
takes advantage of every feature of the underlying hardware
and I/O loads that give the best results. For example,
vendors will run a load of single sector, sequential reads
to reduce the affects of seek time. Other vendors will
use loads that approximate real I/O loads with the seek
range somewhat limits, a mix of reads and writes and
specify a response time to go with the request rate.
You have to look closely at the vendor's documentation
to figure it out.
What are you using to measure the I/O rate seen by the
database software? If the database itself, then you
may be seeing the affects of caching, where it doesn't
have to do any real I/O much of the time. You can use
iostat(1) to see what the real I/O rates are.
Thanks again
>>> Andrew Tolmie <Andrew.Tolmie_at_Carltonscreen.com> 08/01/01 03:17pm >>>
Guy's,
Forgive me for asking this if it's a dumb question -
On my database server during, for example, Order Import in Oracle Manufacturing I am seeing large amounts of IO/sec - averages between 18-20,000 but reasonably low amounts of data transfer. This server is currently using MYLEX DAC960 SWXCRs which have a rating of 2,716 IO/sec.
Can anybody please explain to me what this rating is and what effect the above would cause on performance - would it seriously slow it down?
Sorry if it's lame!
Andy
This e-mail and any attachment is confidential and may be legally privileged. It is intended for the named recipient only. If you have received it in error, please do not forward it or copy it or act upon its contents,
but report it to postmaster_at_carltonscreen.com
Any dissemination, distribution, copying or use of this communication without the permission of the addressee is prohibited.
The contents of an attachment to this e-mail may contain software viruses, which could damage your computer system or data. While Carlton Screen Advertising Ltd has taken reasonable precautions to prevent the inclusion of viruses in e-mails and attachments, neither it nor the sender can accept any liability for any loss or damage sustained as a result of software viruses. You are strongly advised to carry out your own virus checking before opening any attachments.
This e-mail and any attachment is confidential and may be legally privileged. It is intended for the named recipient only. If you have received it in error, please do not forward it or copy it or act upon its contents,
but report it to postmaster_at_carltonscreen.com
Any dissemination, distribution, copying or use of this communication without the permission of the addressee is prohibited.
The contents of an attachment to this e-mail may contain software viruses, which could damage your computer system or data. While Carlton Screen Advertising Ltd has taken reasonable precautions to prevent the inclusion of viruses in e-mails and attachments, neither it nor the sender can accept any liability for any loss or damage sustained as a result of software viruses. You are strongly advised to carry out your own virus checking before opening any attachments.
Received on Thu Aug 02 2001 - 15:47:06 NZST