Re: [GENERAL] Upgrade to dual processor machine?

> 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.

  "doubling performance" is very conservative, I've seen it give more than
a tenfold increase in performance on large insert/update batches.  Of
course, the exact figure depends on a lot of hardware and OS factors.

> 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.

   If you trust the hardware, disabling fsync and using copious quantities
of cache/buffer can almost eliminate actual disk access.  My DB machine
will quickly blip the lights on the RAID array once a minute or so, but
that's about it.  All of the actual work is happening from RAM.  Of
course, with obscenely large data sets, that becomes difficult to achieve.

steve