Re: Huge Email Service
On Tue, 30 Nov 1999, Florian Kunkel wrote:
>... think about a solution whitout NFS (cause "it's quite unforgiving").
>
>the proxy concept takes advantage of the semi/quasi atomic POP3
>operations and it performs faster then NFS does.
>the POP3 client has to ask for any single message to fetch - imagine the
>POP server crashes right at that moment - then the proxy allready has
>transfered some messages successfully and can give a message like "no
>new mails" or "system unavailable" whitout any harm to the mails that
>can be fetched later.
>this system relys on MailDir format.
Currently if a POP server dies during transfer you won't lose data, the
worst-case scenario with correctly written POP serving software is receiving
mail twice.
A POP proxy can be part of the solution. However it doesn't solve the issue
of redundancy over file server failures. I guess you could have two PCs with
dual-ended SCSI between them talking to the RAID array. Or you could have a
pair of NetApp Filers and talk to them from a number of servers over NFS.
Maybe NFS will halve the speed, so you add twice the number of servers. For
a serious network it won't matter.
>Russell Coker wrote:
>> Also you have to make sure that mail delivery and POP locking is in the same
>> place.
>> If you get it wrong then mbox format is quite unforgiving of NFS problems.
>> I recommend using Maildir storage for any serious mail server as it is
>> much more NFS friendly.
--
Electronic information tampers with your soul.
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