Watching performance on a DHCP Server
john at iastate.edu
Tue Feb 12 22:40:37 UTC 2008
> > > I really don't understand the numbers people are quoting here. We use
> > > a Dell 1850 with one 3.2 GHz CPU, one Gig of memory and two SCSI disks
> > > in battery backed hardware RAID 1. We use this to serve 100K customers
> > > with 24 hour leases. No problems whatsoever, and we feel we have plenty
> > > of room to grow.
> > If a raid array is configured to signal write complete as soon as
> > the data is in the array's cache that can have a tremendous performance
> > advantage - at the cost of possibly losing the data should the raid
> > controller catch fire or something before the data actually makes
> > it to the disk.
> Obviously. However, I think battery-backed RAID caches that signal
> write complete as soon as the data is in the array's cache is "fair
> game". I don't consider the risk of losing the *RAID controller* to
> be significantly higher than losing the disks themselves (probably
> quite a bit *lower* in real life since it has no moving parts).
I don't think it's unreasonable (for most) either,
but it may well explain why, in an fsync-bottlenecked
app, you see better perfomance than those without it.
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