Re: Background writer underemphasized ...

On Wed, 16 Apr 2008, Bill Moran wrote:

>> bgwriter_delay = 10000ms         # 10-10000ms between rounds
>> bgwriter_lru_maxpages = 1000     # 0-1000 max buffers written/round
> Have you watched closely under load to ensure that you're not seeing a
> huge performance hit every 10s when the bgwriter kicks off?

bgwriter_lru_maxpages = 1000 means that any background writer pass can
write at most 1000 pages = 8MB.  Those are buffered writes going into the
OS cache, which it will write out at its own pace later.  That isn't going
to cause a performance hit when it happens.

That isn't the real mystery though--where's the RAID5 rant I was expecting
from you?

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD