5 ms·

I've been running my own mail servers since the mid-90s, and always only a single server. SMTP keeps retrying, so you can be offline. The transport layer was de

by KayEss 9y ago

I've been running my own mail servers since the mid-90s, and always only a single server. SMTP keeps retrying, so you can be offline. The transport layer was designed to deliver mail to servers even if those servers only dialled in to one of the "internets" once per day, so it's fine to have some downtime. It's totally up to you how you prioritise getting a server back up again, and frankly if the message can't handle at least a few hours delay then email probably isn't the right medium for it.

cat199 9y ago
caveat: keep your DNS up always - so have a backup if this is running DNS - many mailing list programs and other things will drop a mail immediately if the destination cant be resolved..
- jessaustin 9y ago
  People running their own mail probably would be less nervous about hiring someone for DNS?
drdaeman 9y ago
This is actually frustrating, e.g. with a large power outage when you expect an important message. I run my mailhost (single-node) since 2005 and I thought that I need HA more than once or twice. Sadly, I haven't figured out a proper fully-redundant solution. Syncing mailboxes with e.g. Syncthing is way too fragile. Recently, I wanted to experiment with DBMail + CockroachDB cluster but haven't yet found time for that. Never found any MRA that uses document-oriented database like RethinkDB; and GlusterFS is way too sensitive to high latencies - so DBMail+CRDB looks like the only readily accessible option sans of trying more "raw" programmable solutions like Salmon or Haraka and writing own storage backend.
- andris9 9y ago
  Redundancy requirement was one of the reasons I started building WildDuck mail server. It can be set up with no-spof components, everything can be replicated. https://github.com/nodemailer/wildduck#no-spof-architecture https://github.com/nodemailer/wildduck#no-spof-architecture
  - drdaeman 9y ago
    Whoa! That's very interesting, thanks a lot! Haven't seen this project before - and I've tried to search for mail servers using document-oriented DBs, although not sure if I've searched specifically for MongoDB. Will definitely take a look.
    - andris9 9y ago
      I guess the project is too new and it is hard to stand out amongst other players that have been around for 20 years by now. Even though not having been around so long has advantages as well, for example it allows skipping non-needed features and adding new stuff like full unicode support – I host андрис@уайлддак.орг on my WildDuck test instance (even though I can only communicate with Gmail using this address, other servers either refuse my messages or do not send to such address).
- quicksilver03 9y ago
  Dovecot has an excellent implementation of 2-way synchronization of mailboxes: run Dovecot on 2 different servers in different physical locations, set up MX records and a SMTP software on both servers and you have your HA solution.
  - drdaeman 9y ago
    Built-in sync causes accidental message duplication in shared folders. Or, at least, it did last time I've tried it, some years ago. (But maybe I should review and simplify my mailbox/account structure... It grew quite messy at the moment.)
heartbreak 9y ago
> frankly if the message can't handle at least a few hours delay then email probably isn't the right medium for it. This may have been the case in the mid-90s, but it is certainly not the case today. I frequently receive emails that require immediate attention, whether from my employer, my bank, or any number of other notifications. Normal email users expect emails to be delivered in seconds, not hours.
- CaptSpify 9y ago
  Then normal users need to adjust their expectations. Email has never been assumed to be immediate. Iirc, its even in the spec
  - Spivak 9y ago
    Of course not, like most things email is best-effort. But it's hard to blame users when for the last 10 years we've been able to send/receive email in <10s.
    - syshum 9y ago
      I feel sorry for you if you base everything on user expectations... I sure hope you do not work in professional IT if that is the case because if you do you must be one stress out person...
- sigstoat 9y ago
  > Normal email users expect emails to be delivered in seconds, not hours. their expectations are unreasonable. gmail, etc don't even manage that much of the time, let alone guarantee it.
  - Spivak 9y ago
    Sure, everything is best-effort on the web but <10s delivery is pretty much the norm now.
    - 9y ago

by KayEss 9y ago

cat199 9y ago

caveat: keep your DNS up always - so have a backup if this is running DNS - many mailing list programs and other things will drop a mail immediately if the destination cant be resolved..

jessaustin 9y ago
People running their own mail probably would be less nervous about hiring someone for DNS?

drdaeman 9y ago

This is actually frustrating, e.g. with a large power outage when you expect an important message. I run my mailhost (single-node) since 2005 and I thought that I need HA more than once or twice. Sadly, I haven't figured out a proper fully-redundant solution. Syncing mailboxes with e.g. Syncthing is way too fragile. Recently, I wanted to experiment with DBMail + CockroachDB cluster but haven't yet found time for that. Never found any MRA that uses document-oriented database like RethinkDB; and GlusterFS is way too sensitive to high latencies - so DBMail+CRDB looks like the only readily accessible option sans of trying more "raw" programmable solutions like Salmon or Haraka and writing own storage backend.

andris9 9y ago
Redundancy requirement was one of the reasons I started building WildDuck mail server. It can be set up with no-spof components, everything can be replicated. https://github.com/nodemailer/wildduck#no-spof-architecture https://github.com/nodemailer/wildduck#no-spof-architecture
- drdaeman 9y ago
  Whoa! That's very interesting, thanks a lot! Haven't seen this project before - and I've tried to search for mail servers using document-oriented DBs, although not sure if I've searched specifically for MongoDB. Will definitely take a look.
  - andris9 9y ago
    I guess the project is too new and it is hard to stand out amongst other players that have been around for 20 years by now. Even though not having been around so long has advantages as well, for example it allows skipping non-needed features and adding new stuff like full unicode support – I host андрис@уайлддак.орг on my WildDuck test instance (even though I can only communicate with Gmail using this address, other servers either refuse my messages or do not send to such address).
quicksilver03 9y ago
Dovecot has an excellent implementation of 2-way synchronization of mailboxes: run Dovecot on 2 different servers in different physical locations, set up MX records and a SMTP software on both servers and you have your HA solution.
- drdaeman 9y ago
  Built-in sync causes accidental message duplication in shared folders. Or, at least, it did last time I've tried it, some years ago. (But maybe I should review and simplify my mailbox/account structure... It grew quite messy at the moment.)

heartbreak 9y ago

> frankly if the message can't handle at least a few hours delay then email probably isn't the right medium for it. This may have been the case in the mid-90s, but it is certainly not the case today. I frequently receive emails that require immediate attention, whether from my employer, my bank, or any number of other notifications. Normal email users expect emails to be delivered in seconds, not hours.

CaptSpify 9y ago
Then normal users need to adjust their expectations. Email has never been assumed to be immediate. Iirc, its even in the spec
- Spivak 9y ago
  Of course not, like most things email is best-effort. But it's hard to blame users when for the last 10 years we've been able to send/receive email in <10s.
  - syshum 9y ago
    I feel sorry for you if you base everything on user expectations... I sure hope you do not work in professional IT if that is the case because if you do you must be one stress out person...
sigstoat 9y ago
> Normal email users expect emails to be delivered in seconds, not hours. their expectations are unreasonable. gmail, etc don't even manage that much of the time, let alone guarantee it.
- Spivak 9y ago
  Sure, everything is best-effort on the web but <10s delivery is pretty much the norm now.
  - 9y ago