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Running mail server on 512MB

VPS Hosting by steveipw 12 replies 8.5K views
steveipw

Member OP

5 #1

Running mail server on 512MB RAM VPS — complete experience report

Specs:

  • Contabo KVM, 512MB RAM, 1 vCPU, 20GB SSD
  • Debian 12, Postfix + Dovecot + Rspamd
  • 3 domains, ~10 mailboxes

Setup took 2 evenings. ZFS on root not practical at this size, went with ext4. RAM usage settled at 380MB with all services. For that money you get barely enough headroom for queue spikes.

Key tuning:

  • Rspamd workers cut to 1
  • No clamav (use milter at gateway instead)
  • Postfix chrooted, minimal milters

Six months later: IP on 3 RBLs. Contabo subnet reputation destroyed by neighbors. SPF/DKIM/DMARC perfect, deliverability still trash. Giving up, moving to forwarding service. Not worth the fight at this tier.

zfs send | zfs receive. repeat.
Craig

Member

scheduled pessimist

4 #2
steveipw said:
ZFS on root not practical at this size

ZFS ARC alone would eat—actually with 512MB you'd be looking at—unless you cap it at 64MB which defeats the—my point was going to be about mirrors but now I'm thinking about RBLs instead—the neighborhood problem is real, I've seen entire /24s burned because one guy runs—what was I saying—right, for hobby mail you need clean IP or it's not worth the headache.

MA

Member

#3

Very cheap only lah, I am buy last year from Hetzner xixixi

But IP is blacklist in 2 month, I am give up also

Now I am use forwarding service, much better xixixi

hankels

Member

52 VPS and counting

#4

52 boxes across 8 providers, 3 do mail

512MB mail server: $3/mo = $0.006/GB/RAM. For that money you get what you pay for.

My numbers:

  • OVHcloud 1GB mail: €4, still alive 14 months
  • Vultr 512MB: blacklisted in 6 weeks
  • Self-hosted at home: $0, but dynamic IP hell

RBL survival = IP reputation + provider tier. Cheap only if you enjoy pain.

seedbox, NAS, tape, and three offsite
pieter_rtm

Member

#5
hankels said:
OVHcloud 1GB mail: €4, still alive 14 months

As said, BGP prefix with clean SWIP helps. Without: lottery.

Specs that matter for mail hosting:

  • Dedicated IPv4 (not shared)
  • Provider with IP reputation monitoring
  • PTR matching HELO
  • TLS 1.3, no exceptions

512MB works. The IP pool does not. We see 40% of budget IPv4 space pre-burned.

Containers before it was cool
minh1987

Member

#6

In my country, ISP block port 25 by default. Must request open with business registration.

How you get clean IP in US/EU? Just buy and go?

phở at 3AM, deploy at 4
TO

Member

4 #7

Hey folks, quick reminder: provider naming is fine for experience reports, but let's keep vendor comparisons factual.

@minh1987 port 25 blocking varies by region — some providers require ticket, others open by default. Worth checking before you buy.

FO

Member

#8

What vCPU generation is that Contabo node?

readerkrakw

Member

Backup Paranoid

#9

I cut rspamd workers to 1 on my 1GB box too, works fine

MA

Member

#10

No clamAV at all? Gateway milter doesn't help if the gateway is you.

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