Richard Huxton wrote:
> Dave Cramer wrote:
>>
>> On 18-Nov-05, at 1:07 AM, Luke Lonergan wrote:
>>
>>> Postgres + Any x86 CPU from 2.4GHz up to Opteron 280 is CPU bound
>>> after
>>> 110MB/s of I/O. This is true of Postgres 7.4, 8.0 and 8.1.
>>>
>>> A $1,000 system with one CPU and two SATA disks in a software RAID0
>>> will
>>> perform exactly the same as a $80,000 system with 8 dual core CPUs
>>> and the
>>> world's best SCSI RAID hardware on a large database for decision
>>> support
>>> (what the poster asked about).
>>
>>
>> Now there's an interesting line drawn in the sand. I presume you
>> have numbers to back this up ?
>>
>> This should draw some interesting posts.
That's interesting, as I occasionally see more than 110MB/s of
postgresql IO on our system. I'm using a 32KB block size, which has
been a huge win in performance for our usage patterns. 300GB database
with a lot of turnover. A vacuum analyze now takes about 3 hours, which
is much shorter than before. Postgresql 8.1, dual opteron, 8GB memory,
Linux 2.6.11, FC drives.
-- Alan
