On 8/21/20 10:15 PM, Caveman Al Toraboran wrote:
just to double check i got you right. due to flushing the buffer to
disk, this would mean that mail's throughput is limited by disk i/o?
Yes.
This speed limitation is viewed as a necessary limitation for the safety
of email passing through the system.
Nothing states that it must be a single disk (block device). It's
entirely possible that a fancy MTA can rotate through many disks (block
devices), using a different one for each SMTP connection. Thus in
theory allowing some to operate in close lock step with each other
without depending on / being blocked by any given disk (block device).
Thank you for the detailed explanation Ashley.
or did i misunderstand?
You understand correctly.
i sort of feel it may suffice to only save to disk, and close fd.
then let the kernel choose when to actually store it in disk.
As Ashley explained, some MTAs trust the kernel. I've heard of others
issuing a sync after the write. But that is up to each MTA's
developers. They have all taken reasonable steps to ensure the safety
of email. Some have taken more-than-reasonable steps.
--
Grant. . . .
unix || die
