more RAM + faster disk -> slower box?!

Nik Clayton nik at
Thu Nov 29 13:24:48 GMT 2001

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On Thu, Nov 29, 2001 at 12:34:38PM +0000, Ian Pallfreeman wrote:
> I have a news server (INN, trad spool) which recently lost a disk, part of
> a mirrored pair holding all news stuff except the articles (i.e. binaries=
> history, active file, overview). The articles are on a RAB 3600 IDE<->SCSI
> RAID, which, frankly, sucks, and has been the cause of much sorrow. The=
> replacement disk is a SCSI 160MB/s, replacing an 80 -- same size, same=20
> geometry. And I took the opportunity to increase the memory from 256MB to
> 768MB, in the hope that this might further compensate for the bandwidth
> problem in the IDE RAID.=20

I know that some older motherboards never cached more than the first
512MB of memory.  This was a particular problem with Windows, because it
was loaded in to the top of memory.  If you had more than 512MB of RAM
you suddenly discovered that your OS was running in non-cached memory,
and everything got slower.

FreeBSD is probably susceptible to the same problems (not sure where the
OS loads, but given FreeBSD's aggressive use of memory you're going to
be hitting that top 256MB very soon after boot).

I don't know whoch motherboards had this problem, but Google can
probably tell you.  It might be worth ripping out 256MB and trying the
test again.

FreeBSD: The Power to Serve   
FreeBSD Documentation Project 

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