Re: VACUUM degrades performance significantly. Database

Stephen wrote:

> Good news,
>
> I partially fixed the problem on Linux 2.4. It appears the responsiveness
> can be improved significantly by tuning the disk IO elevator in Linux using
> "elvtune" in util-linux. The elevator in Linux is used to re-order
> read/write requests to reduce disk seeks by ordering requests according to
> disk sectors. Unfortunately, the elevator in kernel 2.4 is not very smart
> (or flexible I should say depending on your needs) and can starve a
> read/write request for a long time if not properly tuned.
> elvtune -r 2048 -w 8192 /dev/hdc (default Redhat 9):
> ====================================================

Are you sure ? In my RH9.0 installation I obtain:

# elvtune /dev/sda7

/dev/sda7 elevator ID           5
         read_latency:           64
         write_latency:          8192
         max_bomb_segments:      6


may be your problem is due the fact that someone change these values
on your machine!



Regards
Gaetano Mendola