Watching performance on a DHCP Server

Olaf van der Spek olafvdspek at
Mon Feb 11 22:46:52 UTC 2008

On Feb 11, 2008 11:37 PM, Blake Hudson <blake at> wrote:
>  The server has eight directly attached 147GB 15k drives... it just happens
> that the leases file is on a RAID 1 array. Without fsyncs, the next limiting


> factor is CPU power... which I hit very quickly at around 40 4-way

What's so CPU intensive about a 4-way handshake?

>  fsyncs are the most I/O intensive operation you can perform on magnetic
> media. If I remember correctly it takes at least 2 full rotations of the
> disk for an fsync to occur, although it may take longer to commit more data.
> This is were solid state rules over magnetic storage.

Why are two required?
Even then, you could commit lots of transactions in a single go.

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