Re: [Exadata] How do you use FlashDisk ?
- From: Surachart Opun <surachart@xxxxxxxxx>
- To: Robert Freeman <robertgfreeman@xxxxxxxxx>, Kerry Osborne <kerry.osborne@xxxxxxxxxxx>
- Date: Sat, 19 Mar 2011 21:51:40 +0700
Thank You for Idea and concerned. That's a great idea Flash Disk on
Exadata..
Best Regards,
Surachart Opun
Oracle ACE, Contributor (Oracle User Group in Thailand)
http://surachartopun.com
skye: surachart_op
On Sat, Mar 19, 2011 at 8:58 PM, Robert Freeman <robertgfreeman@xxxxxxxxx>wrote:
> Flash disks for WRITE operations are actually not that fast. I don't have
> the performance numbers here, but you really don't buy anything in terms of
> write performance with flash disks. So I would not recommend them for a disk
> group that will contain, say, online redo logs.
>
> Also, with the Flash on Exadata keep in mind that it's a write through
> flash. Thus, the data cached in Flash is not based on what is written to the
> disks or read from them, but rather there is an algorithm that Oracle uses
> to determine what is put in flash and what is not. For example, large table
> scan blocks or large table loads are NOT going to to populate the flash
> cache, whereas frequently used blocks will. This makes the flash disks very
> much one of the key ingredients for the OLTP performance that we get on
> Exadata.
>
> Cheers!
>
> Robert G. Freeman
> Master Principal Consultant, Oracle Corporation, Oracle ACE
> Author of various books on RMAN, New Features and this shorter signature
> line.
> Blog: http://robertgfreeman.blogspot.com
>
>
> ------------------------------
> *From:* Surachart Opun <surachart@xxxxxxxxx>
> *To:* "Oracle-L@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
> *Sent:* Sat, March 19, 2011 2:34:48 AM
> *Subject:* [Exadata] How do you use FlashDisk ?
>
> On Exadata, You will have flashdisks. Idea to use them:
> A. Make them for Exadata Smart Flashcache
> B. Use them for Grid Disk for ASM Disk Group, and store some database
> files.
> C. Use both A and B in Database System
>
> I just curious, What should I concern, if use Flash Disks to be Grid Disks.
> What is you idea to use Flashdisk? However, Database System supports both
> OLTP and DSS.
>
> Thank You
> Surachart Opun
> Oracle ACE, Contributor (Oracle User Group in Thailand)
> http://surachartopun.com
> skye: surachart_op
>
>
>
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