Watching performance on a DHCP Server

[Simon Hobson]

Blake Hudson wrote:

>Seems like it would make sense that this I/O could be 
>non-blocking.... e.g. leases are served out of memory and the log 
>sent to disk. If the disk cannot keep up, too bad, let it queue.
>
>I would see the value of making this an option on startup, those who 
>are paranoid can keep an up to date log on disk. Those who have done 
>due diligence with a battery backed up RAID device and redundant 
>power have the option to allow the writes to be combined, queued, or 
>otherwise managed by the filesystem or block devices (which we can 
>assume are configured to fsync when appropriate).

It's part of the spec - the lease data must be stored in non volatile 
storage before being offered to the client.

I guess systems are a bit more reliable now than when the spec was 
written, but it still makes sense. As you've found out, simply 
enabling write-back in your RAID controller can take away much of the 
overhead.