Re: WAL write of full pages

Поиск
Список
Период
Сортировка
От Manfred Spraul
Тема Re: WAL write of full pages
Дата
Msg-id 40569C37.1070001@colorfullife.com
обсуждение исходный текст
Ответ на Re: WAL write of full pages  (Marty Scholes <marty@outputservices.com>)
Список pgsql-hackers
Marty Scholes wrote:

>
> 2. Put them on an actual (or mirrored actual) spindle
> Pros:
> * Keeps WAL and data file I/O separate
> Cons:
> * All of the non array drives are still slower than the array

Are you sure this is a problem? The dbt-2 benchmarks from osdl run on an 
8-way Intel computer with several raid arrays distributed to 40 disks. 
IIRC it generates around 1.5 MB wal logs per second - well withing the 
capability of a single drive. My laptop can write around 10 MB/sec 
(measured with dd if=/dev/zero of=fill and vmstat), fast drives should 
be above 20 MB/sec.
How much wal data is generated by large postgres setups? Are there any 
setups that are limited by the wal logs.

--   Manfred




В списке pgsql-hackers по дате отправления:

Предыдущее
От: Tom Lane
Дата:
Сообщение: Re: Reducing expression evaluation overhead
Следующее
От: Greg Stark
Дата:
Сообщение: Re: Reducing expression evaluation overhead