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The Truth about Migrating from Domino to Microsoft (Mail Edition)

Look Before You Leap

In this article we describe our real life experience of migrating from Notes/Domino to Microsoft Exchange and Exchange online.

To be clear we have a vested interest here. We don’t want any of our customers to migrate from HCL Domino to any other platforms. However we also do acknowledge that we have got business from migrating customers from Domino to Exchange/Exchange Online (and indeed we’re the only certified experts for Quest Migrator from Notes to Exchange in Ireland).

On the mail end of things from our experience generally the driver for a migration is a combination of factors. Almost inevitably this involves

  1. A personality high up the food chain who decides they want Outlook and/or

  2. Microsoft sales have been aggressive in telling you that you can migrate everything in two days and it’ll be so much cheaper and better.

We have never seen a migration based on a logical technical decision. However on every single migration we’ve ever done we’ve cringed at the cost involved to essentially get a like for like platform for end users. Some things will be slightly better, some things will be slightly worse. But lets be honest lads, from an end user perspective ultimately email is email. Others have spent plenty of time and effort telling us Notes is dead. Microsoft is king. Long live the king. It’s the complacency that gets in the way of the actual truth in what is involved in a migration from Domino to Exchange.

It’s difficult here because we don’t want to get too much into the weeds on details but there are general trends that we have found on dozens of small, medium and large migrations of Notes based mail to Exchange:

Be prepared to spend exponentially more money on hardware to do the same thing. There are several reasons for this. Firstly DAOS. With DAOS turned on Domino stores attachments efficiently. Once an attachment is above a certain specified size then it’s stored centrally in an encrypted repository, one per server. If you’ve used Domino in the last 12 years or so you’ll know it’s easy to turn on and it whirls away in the background. Exchange used to have single instance storage but moved away from that model ultimately because disk space was becoming cheap. SANs were in vogue. The irony is now any Exchange environment I’ve seen recently is not SAN attached and has expensive SSDs in a bare metal server. DAOS can save you 60-90 percent the amount of disk space on a Domino server. If you are using SSDs and sophisticated RAID setups this can be a significant cost differential.

Secondly even with DAOS disabled Domino stores data much more efficiently than Exchange. Particularly richtext. We have actually put our own numbers on this from practical experience. With DAOS disabled Domino will store data 1.2 to 1.9 times more efficiently than Exchange. A practical example here might illustrate the point. If you’ve a 10 GB (logical sized) Notes mail database, savings via DAOS mean that it’s actually only taking up 1 GB of physical disk space. If you migrate that 1GB of physical space to Exchange it could potentially take up to 1.9 times the unDAOS’ed size, it could be 19GB of physical space in Exchange. I’ll say that again for the people whose eyes glazed over when numbers came into it. 1 GB physical storage mailbox in Notes could easily equate to 19 GBs of physical mailbox storage in Exchange. You multiple that by 1000 or 10,000 users and your accountant is getting the sweats. We wonder why no one from the business pauses at this point and says, “hold on a second what’s the total cost of this again and what are we gaining”?

That’s just looking at like for like comparisons. Generally Exchange infrastructure just requires more servers. If you take a basic Domino mail cluster on a relatively small site. They’ve 2-3 locations, they’ll likely have 2 to 3 Domino servers. For arguments sake we’ll say 3. They’re clustered. No extra hardware is involved because Domino has native clustering (from Domino 10 it even self heals). Even the most basic Microsoft setup of the same thing will have 2 servers per site with potentially multiple separate load balancers required (did we mention Exchange doesn’t have native clustering?). So you’ve now double the amount of servers(At least 2 servers per site across 3 sites would be the most basic standard setup), with much, much more disk space(and again extra appliances for load balancers). If we go back to that 1 GB physical mailbox in Notes, across three servers that’s 3GB in Domino physical storage in this small site. In Exchange it’s 19GB across 6 servers or 114GB. So 3GB of physical storage of a mailbox in Domino could be 114GB for essentially the same thing in Exchange. THAT IS NUTS. Extra hardware in load balancers also need to be purchased and managed. Your backups are going to be more expensive and running for longer. The Microsoft sales guy didn’t mention any of this in his pitch.

That’s before we even get to RAM and CPU. Most responsible Exchange Architects will put numbers/metrics into a Microsoft form to give you the specs of the Exchange servers for the greenfield site. They will be spec’ed tens of times more expensive than your current Domino servers and again there’ll be more of them. We might add that on least two migrations we’ve worked on, where the customer did spend the recommended cash on the new servers – post migration it was realised they actually we’re underspec’ed and they’d to add specialised extra RAM running into costs of six figures (which was more than Domino servers infrastructure running on virtual machines cost in total). That’s on top of the initial capital spend running into hundreds of thousands of euro.

Ok so I think we’ve laid out that will cost you a lot of money, an awful lot of money for essentially the same user experience, even if everything goes perfectly that’s before the cost of modifying existing Domino apps that will break, or the actual cost of someone managing the migration for you, which can be big or small depending on the complexity of your Notes apps. And we haven’t even mentioned that unless you’ve no Domino applications you’ll likely still be paying for Notes/Domino licences and now Exchange/Office 365 licences so your licensing costs are at least doubled.

Maybe you decide you’ll avoid much of that by going to Office365. Microsoft will tell you it’ll cost a tiny amount per user (unless you want luxury items like backups).

The second point (particularly applicable to Office365) is security. Has your Domino infrastructure ever been hacked? We can’t ask/state it enough. Domino is rock solid on security compared to Exchange Online. It sounds trite but if you move your mail to Exchange Online you will get accounts hacked. Every month. Yes, they are improving some things like multi factor authentication. Yes, the the sales guy will tell you they spend more on security than any other cloud vendor. But that’s for a very good reason. Being hacked on Exchange Online is inevitable. They even have technotes for you to tell you what to do when it does happen –

There’s also the big dirty secret, that isn’t really a secret but no one wants to talk about, and that’s data residency in Exchange Online/Office365. Yes you can select your preferred location for your cloud data. But under their terms and conditions Microsoft can move that data to anywhere in the world without telling you. It’s kind of the point behind cloud services but if you have sensitive data. try explaining that to your Data Protection Officer. As a follow up, the costs for Exchange Online are not the per user costs that are set out, there’s add ons if you want basic options on backups for example. Also we’ve received many reports of the performance being flaky –

Your users will not suddenly stop complaining about mail on the new platform, in fact it may be worse than before. You will be asked “where is my all docs view”, you will be asked “why is search so slow” “or I can never find anything”, they won’t like that weekly repeat meeting for ten years with multiple exceptions, worked fine in Notes and doesn’t in Exchange. “I used to be able to do it this way and I want to do it exactly the same way”

You or your Domino Administrator will miss the Domino Console. I can’t over emphasis this enough. From an Admin point of view the Domino console is the single best differentiator of Domino from anything else. It’s REACT for servers. I’m the first person to tell you the Admin client as a whole could do with an update but the Exchange Admin Interface is horrible. To do most tasks you need a doctorate in PowerShell. I do actually like PowerShell, it’s powerful and it works but it should be an addendum to a proper admin console not the start and finish of it.

With all that being said, if you’re prepared to spend all the money for a similar platform, a mail migration is doable if you find the right consultants (i.e. Domino People). Anyone who’ve we migrated was happy with the migration itself running smoothly. You shouldn’t do a risky big bang migration, you can stagger it using foreign SMTP domains with a relatively short window without freetime lookups between the environments you shouldn’t need a third party co-existent product. Contrary to popular belief, in general Notes links will work fine over SMTP.

And one more thing after you’ve spent all the money and gone through all the heartache. A year later, more people than not will say “I miss Notes”. That’s before we get into the investment made by HCL the past couple of years. (here’s just a flavour of what’s been going on around Notes, just this summer in the middle of a pandemic – Really the question is, why would you migrate now?

Think twice and look before you leap.

Cormac McCarthy – Domino People Ltd

8 thoughts on “The Truth about Migrating from Domino to Microsoft (Mail Edition)

  • I can agree with you on all points, written very well and in detail. And this is only the tip of the iceberg, if there are still many applications in the game, it usually gets really dramatic.

  • With daos sizing of your 10gb mail file you say it reduces to 1gb… does that take into account the size of the files in the daos folder?
    I feel you only get gains there with scale as more users have the same file attached in their mailfile.

    • Cormac McCarthy says:

      Hi Robert,

      It’s an illustrative example as much as anything, but yes you would need scale to get that type of reduction with DAOS, but the ratio of a reduction is not particularly unusual from our experience.

  • Curious Visitor says:

    It‘s amazing how biased your view on security above is – it‘s not about Exchange being hacked, but accounts being hacked due to weak passwords and missing 2FA. The same will happen on Domino (or any IT system) if you don‘t enforce proper password policies, 2FA and access restrictions. Of course you can hide your servers behind within your company network for an additional layer of Security, but the same is possible with exchange. Even Microsoft365 can be Limited to access from your network‘s breakout IP ranges. The difference is M365 will try to detect and block those attempts while Domino has no built-in security analytics.

    • Cormac McCarthy says:


      I agree that the premise of exposing accounts to the web is the main issue with Office 365, but the issue remains.

      And the other point remains too, you are much, much, much likelier to get hacked with Exchange (even on premise) than Domino.

      And to be fair we did lay out our bias on the second line. Though nothing we said here is untrue.


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