Re: Postgresql on software RAID

On 17/12/03 3:45 pm, "scott.marlowe" <scott(dot)marlowe(at)ihs(dot)com> wrote:

> On Tue, 16 Dec 2003, Robert Creager wrote:
>
>> When grilled further on (Tue, 16 Dec 2003 22:30:04 -0600),
>> Patrick Spinler <spinler(at)kmtel(dot)com> confessed:
>>
>>>
>>> According to the theory they expound, a database with any significant
>>> write activity whatsoever should never be on raid 5, but instead be on
>>> raid 0+1.
>>>
>>
>> Kind of related and a point of reference. We use ClearCase and have many
>> multiple Gb vob's(databases). We were using RAID-5, but had to back off to
>> RAID
>> 0+1 because of performance reasons (which was indicated in the manual, once
>> you
>> read it...). This would happen around 1-2Gb's vob size. Our usage of CC
>> provides heavy writing activity to the underlying dB.
>>
>> I don't know what kind of dB engine Atria->Rational->IBM has implemented
>> underneath, or even it it would look like a dB to someone who knew the
>> difference...
>
> Just wondering, was that on hardware or software RAID5, and if hardware
> did it have battery backed cache controllers? Makes a huge difference. I
> would never use SW RAID5 for heavily written databases.

Hi Scott,

What level of activity would you call "heavily written"?

Thanks

Adam

--
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.