I need some infomation about Spamassassin. I will have to manage more than 25 000 mail account (between 400 000 and 1 000 000 mails per day) and i need a very good anti spam software. I would like to know if SpamAssassin can handle a so large number of email account.
Sourceforge uses SpamAssassin on their mailing lists last I checked. That's a LOT of mail volume.
There are others on the list that are doing pretty large volumes too. Maybe some of them will chime in and give you an idea of what kind of hardware you need.
Do you think that SpamAssassin is better than the other commercial anti spam software for that use ?
Define "better".. In terms of accuracy, SA in the upper tiers, and certainly better than most commercial and non-commercial products.
However, there are some commercial tools which are on the same par and possibly better. I do not have a lot of detailed testing comparing the various tools, but I've seen a LOT of crappy commercial products, and I've seen some decent ones too. The same can be said of other open-source projects SA is certainly better than most, but there are some other open source projects that work well too.
My favorite is one particular spam/content filter that triggers on the word "vulnerable". This is always fun on security lists. "Garbageware blocked your email because it contained a sensitive content".
As for the rest, the upsides and downsides of SA are going to be similar to most other OSS products.
Advantages:
No direct costs
Decent number of helpful members of the user community.
Disadvantages
Lower quality documentation
No formal tech support
