Re: Oracle Disk Configuration question.

Daniel Morgan wrote:

> Michael Austin wrote:
>

>> I understand the argument of "don't use RAID5", but in my experience, 
>> one of the things you must know about your environment when deciding 
>> on these sort of things is the mix of transactions.  I have been in an 
>> environment that was 75/25% read/write. So the read benefits of RAID5 
>> were well suited to the application.

Well, that depends on the amount of data being read.. If it is a lot (ie greater than the chunk size) then you have many chunks returned concurrently as opposed to serially. They eventually get put back togehter, but reading many disk blocks at a time is much faster... and depending on the amount of data requested, you will get a greater degree of parallelism - which is always faster than serial.

>
> The sole caveat I would put on Sybrand's statements is that in a SAN
> or NAS configuration you are writing to a cache, not to disk, so the
> penalty often is not visible to the application.
>

-- or visible to the user... and you are writing at fibre speeds of 1,2,4 or 10Gb/sec depending on your gear/cabling.

M. Received on Wed Jun 02 2004 - 16:18:18 CDT