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On Sat, Aug 22, 2020 at 04:15:38AM +0000, Caveman Al Toraboran wrote: |
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> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ |
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> On Saturday, August 22, 2020 12:10 AM, Grant Taylor <gtaylor@×××××××××××××××××××××.net> wrote: |
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> |
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> > There is some nebulous area around what that actually means. But the |
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> > idea is that the receiving server believes, in good faith, that it has |
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> > committed the message to persistent storage. Usually this involves |
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> > writing the message to disk, probably via a buffered channel, and then |
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> > issued system calls to ask the OS to flush the buffer to disk. |
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> |
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> just to double check i got you right. due to |
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> flushing the buffer to disk, this would mean that |
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> mail's throughput is limited by disk i/o? |
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> |
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> or did i misunderstand? |
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> |
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> i sort of feel it may suffice to only save to |
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> disk, and close fd. then let the kernel choose |
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> when to actually store it in disk. |
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|
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When an M.T.A. encounters mail, the content of the mail will first exist in the |
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M.T.A.'s local memory, in a buffer. Before sending an "OK" to the sending |
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server, it should first make an attempt to write it to disk, through an fwrite |
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(stdio) or write (POSIX) call. At that point, it is, in theory, the kernel's |
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choice if and when it is _actually_ written to disk, but if one of the |
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aforementioned functions return a success code, the M.T.A. has done its bit, and |
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can consider the message "safely stored". |
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|
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-- |
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|
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Ashley Dixon |
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suugaku.co.uk |
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2A9A 4117 |
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DA96 D18A |
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8A7B B0D2 |
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A30E BF25 |
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F290 A8AA |
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