Re: Upgrade to dual processor machine? - Mailing list pgsql-general

From scott.marlowe
Subject Re: Upgrade to dual processor machine?
Date
Msg-id Pine.LNX.4.33.0211141251500.1942-100000@css120.ihs.com
Whole thread Raw
In response to Re: Upgrade to dual processor machine?  ("Henrik Steffen" <steffen@city-map.de>)
List pgsql-general
On Thu, 14 Nov 2002, Henrik Steffen wrote:

>
> hi steve,
>
> why fsync? - what's fsync? never heard of it... google tells
> me something about syncing of remote hosts ... so why should I
> activate it ?? ... I conclude, it's probably disabled because
> I don't know what it is ....
>
> it's a raid-1 ide system

fsync is enabled by default.  fsync flushes disk buffers after every
write.  Turning it off lets the OS flush buffers at its leisure.  setting
fsync=false will often double the write performance and since writes are
running faster, there's more bandwidth for the reads as well, so
everything goes faster.

Definitely look at putting your data onto a Ultra160 SCSI 15krpm RAID1
set.  My dual 80 Gig Ultra100 IDEs can get about 30 Megs a second in a
RAID1 for raw reads under bonnie++, while my pair of Ultra80 10krpm 18 gig
scsis can get about 48 Megs a second raw read.

Plus SCSI is usually MUCH faster for writes than IDE.


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