[collectd] High load

[Poil]

Hi,

We have a thousand servers  collected on our first collectd server node
The interval is set at 60 on every server

Our load average is about 3, with a lot off wait-io.
The raid 10 volume is composed by 8 drives at 15 000 tour per minutes, 
the raid card has got 512Mb cache which is enable in write-back mode

Our current rrdfile settings :
CacheFlush 200
CacheTimeout 120

Before we had this
CacheFlush 120
WritesPerSecond 100

I've seen no change in our load average/io-wait.

Have-you got any idea for reducing my io-wait ?

Best regards,
Benjamin