I would be concerned about file locking if the mail files are on NFS.
If the primary machine goes down, there are no guarantees that it will
release the NFS locks before it goes down, and you would be just left with
the same problem as before.
I would have instead chosen a redundant hardware configuration with only one
effective machine being the mail spooler.
This machine could use a RAID-1 or 5 hot swap hardware arrangement so that
if one disk fails, you don't use the lot. Hot swap CPUs would be nice but
even more expensive.
It all depends on how much you need the thing to be up.
If you go for redundant disks, say, but non-redundant CPU, then for the
short time a failed processor is down (of course you have a spare on hand)
your ISP just caches incoming mail and your users cache outgoing mail.
When you plug in the new CPU (or whatever it was that failed) the thing just
starts up again on the same disks as before and everyone should be able to
retrieve / send their mail again.
Well that's the theory anyway.
Loss of power: use a UPS for a while or for short outages, then rely on ISP
caching until you can reconnect.
Regards,
Jill.
___________________________________________
Jill Rowling
Snr Design Engineer & Unix System Administrator
Electronic Engineering Department, Aristocrat Technologies Australia
3rd Floor, 77 Dunning Ave Rosebery NSW 2018
Phone: (02) 9697-4484 Fax: (02) 9663-1412
Email: [EMAIL PROTECTED]
-----Original Message-----
From: John Ferlito [mailto:[EMAIL PROTECTED]]
On Tue, Oct 24, 2000 at 10:07:23AM +1000, Marshall, Joshua wrote:
> Does anyone know of a good method to make an email system redundant, so
> that if one server goes down (power loss, network loss etc) the users
> can still retrieve and send emails ?
<snip>
Unless you have a third box which NFS
servers /var/spool/mail then you could setup both boxes as primary MX's
and allow either of them to deliver. But you need to make sure you get
locking right.
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