vdelivermail excessive processes

I have a reoccuring issue of waking up in the morning and finding 5-10 vdelivermail processes in top all eating the cpu too 0% idle and loads above 15. This is a dual xeon 3.0 with 2GB ram and sata 2.0 disks.

We get a large amount of mail flow on our server so I expect some load, but certainly not this much and especially from qmail.

Were the accounts being delivered too at their quota limit? I’ve seen a few cases where this occurs when the linux quotas have been met.