Re: [exim] Spamassassin + Exim4 high IO Wait

Mark Adams wrote:
> I was hoping to draw from the pool of experience that the exim mailing
> list has, as I realise this is a spamassassin or other issue. We are
> running exim4.62-4 with Spamassassin 3.1.4-4 and suffering extremely
> high IO Wait times on the server whenever spamassassin scans an incoming
> email. Exim4 is setup as defaults (spamd running locally on standard
> port) so no configuration was changed. Spamassassin has not had any
> rules added to it. The server goes from 1-2% wait times spiking to
> between 20-90% when spamd is scanning an email, this lasts for a few
> seconds and then drops back down to normal. This is a system with raided
> SATA drives on a LVG that also serves small SMB shares. It serves around
> 40 mail users.
>
> I have not had this problem on servers with SCSI drives, or on servers
> that use SATA but are strictly mail servers.

Traditionally I/O wait time is, as far as the processor is concerned,
just another sort of idle time. If you had more cpu work to do they'd
be doing it.

As to why you've not seen it with SCSI drives, I'd suspect buggy
drivers not reporting waits properly.

In short - you're doing I/O. Don't worry.

- Jeremy