Impact on high volume of email notifications

I am just trying to figure out the best route to take when a CB/CBSubs powered site grows enough that Private messages increase in volume.

There would be an increase in email notifications and I am unsure if PHP Mail can handle it over other options. There is also the concern of ISP flagging the domain sending high volumes of emails as spam.

The other area is the sheer volume of messages that are logged and stored in the site. Is there anything to be concerned about or I should plan in terms of scaling up.

What volumes, should I be looking at before any of this is of major concern.

All of our database queries are bench marked to over a million database rows. This means the database queries are designed for extremely large amounts of data. You shouldn't have anything to really worry about in this regard and with CB 3.x we'll be making further optimizations to all our database tables. You also have the option of making further adjustments to the database (e.g. additional table indexes) in the future if you need some additional optimizations.

As for emails it really shouldn't ever be a problem. Email performance is only really an issue when you need to send an email to a massive amount of recipients (e.g. a newsletter) and queue through them. Regardless you can offload emails to a separate SMTP mail server if you're concerned about it slowing down the main server. With CB 3.x we'll be reviewing a way to bundle emails/notifications into digests so non-important emails could be delayed for example and only sent once daily. Not sure on the details for that yet, but that's the idea at least.

Excellent. This is all comforting news, putting my mind at ease!