Peter de Haas still thinks Exchange’s single instance store is "fairly powerful"

December 5 2005

As a tribute to being in Peter's country, I'm offering a link to his blog for the first time in a while...you're welcome for the traffic, Peter. :)

The occasion?  Another example of Microsoft's insistent belief that Exchange's single instance store is a competitive advantage for Exchange.   I'm not sure what article Peter is quoting in this blog entry, but he writes:

If a message is sent to one recipient and it is copied to 20 other recipients who reside in the same mailbox store, Exchange maintains only one copy of the message in its database. Pointers are then created. These pointers link both the original recipient and the 20 additional recipients to the original message.
Yeah, been there, done that, have lots of t-shirts.  It was called cc:Mail and it was a huge problem.  Why?  That shared store gets corrupted and bam! the whole post office was down.  In Exchange 200X, they have this problem times 20 -- because Exchange actually doesn't have a single store anymore, they support up to 20.  And oh, with no management tools to help an administrator decide which of the 20 storage groups to put a user's mailbox in.  I can't see how MS can represent this as a competitive advantage with a straight face -- I even saw a customer presentation recently where they tried to cost justify a migration based on this one feature alone (!).

At any rate, Bill Buchan and Paul Mooney have the points right in their comments on Peter's site.  Mr. Mooney writes "Disks are cheap - downtime isnt.".  It's that simple.  Domino's single mailbox per user architecture prevents a lot of service interruptions -- and when combined with the only viable active/active shared-nothing clustering, this is why so many Domino environments run 99.999%+ available.  Simple.

Ed Brill | Amsterdam, Nederland Category:  Microsoft  Add/View Comments [16]

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  1. 1  Bill Pappert  | 12/5/2005 2:50:00 PM

    If the single message store were that big a selling point, one would presume that the Domino single message store would be in more wide usage. I've not seen it often. Perhaps in the days of expensive storage or slow access times, a single store made more sense.

    Friend of mine says "Friends don't let friends use the single message store." Add that to Mr. Mooney's "Disks are cheap - downtime isn't" and that's all I need to know about having that single point of failure running in my environment.

  1. 2  Paul Mooney http://www.pmooney.net | 12/5/2005 3:09:21 PM

    Good point Bill...

    As a side note I have got single instance store of Domino running on one site (shared mail in Lotus-speak). Since ND6, it works quite well... but it doesn't give me that warm fuzzy safe fealing that the usual configuration does...

    Don't forget that any mobile user that has a local replica of his mail file never even notices this feature... all his/her mail replicates straight to their laptop... no problem..

    I think most Lotus and large scale customers were burned in the cc:mail/MS mail days... That lesson is still valuable... Go for individual mailboxes and stick it on a SAN if you want.. Then cluster it with a server that isn't on the SAN.. Differnt hardware - no problem

    Differnt OS - no problem

    Different version of Domino - no problem

    Now thats a warm fuzzy feeling....

  1. 3  Paul Mooney http://www.pmooney.net | 12/5/2005 3:10:19 PM

    also... just a warning to Peter....

    Ed's links are bad for your inbound bandwidth... ;-) I love seeing my hit count after being /Ed dotted.......

  1. 4  Peter de Haas http://www.peterdehaas.com | 12/5/2005 4:10:13 PM

    I love it, all this attention. And all because you are visiting The Netherlands ... thanks Ed.

    The offer to buy you a beer still stands (the recordbreaking number of hits of December last year)

    I will update the post by the way as you've rightfully remarked the link the the quoted piece is missing ...

  1. 5  Richard Schwartz http://www.rhs.com/poweroftheschwartz | 12/5/2005 4:36:21 PM

    Single instance mail store: it's older than Exchangne or cc:Mail!

    Manual trackback: { Link }

    -rich

  1. 6  Darren http://www.dadams.co.uk | 12/5/2005 6:18:35 PM

    As I've mentioned before on Ed's blog... number of Exchange customers I've met who lost ALL of their e-mail due to corruptions = 2. Does the single instance of e-mails help this happen?

    Also, I've just read thru a customer's own evalutaion of Domino vs Exchange. They mention that a corruption of the Exchange store will take them 12 hours to put right, but with Donino it'll take them less than 1 hour. "Disks are cheap..." and TCO is made up of many factors. Being lynched by angry users who have no e-mail service isn't very often factored in.

  1. 7  Darren http://www.dadams.co.uk | 12/5/2005 6:20:00 PM

    I can't believe I typed 'Donino'... perhaps I should go to bed.

  1. 8  Brian Benz http://www.softwaresoapbox.com | 12/5/2005 6:34:14 PM

    My thoughts here:

    { Link }

    "My take? I remember seeing a presentation on a VERY early version Notes at the Westin Bayshore in 1990. One of the things that the presenter said back then, which was revolutionary - "Notes is not designed to save you disk space.""

  1. 9  Eric Parsons startingblockcomputing.com | 12/5/2005 8:18:51 PM

    @3 "Ed-dotted." How funny.

    I'm guessing that Domino's SCOS is better than it used to be, but I'm with the majority here. I'd rather rebuild one database with an angry executive tapping his or her foot than several hundred regular Joe's (no offense intended Joe) telling the executive what a weiner I am.

    Not only that, I have a warmer feeling of security if the entire file isn't "open" to multiple users. I know, (don't throw eggs), the system is the only one to have access to the file. Right?

  1. 10  Sean Burgess http://www.phigsaidwhat.com | 12/5/2005 11:29:46 PM

    I've had my say here { Link } and here { Link } so I don't have much to add here. One thing that isn't mentioned it the impact that clustering can have on restoring individual mail files that get corrupted. In less than 5 minutes, you can delete the dead mail file and replicate a new copy from a clustered server and the user may not even know anything happened.

    Sean---

  1. 11  Wild Bill http://www.billbuchan.com | 12/6/2005 2:15:35 PM

    The scary thing is that Exchange STILL runs on Jet - you know the database they derived from ACCESS. Yup. Not even Foxpro.

    And of course the Kodiak - "We'll run on SQL" upgrade - was scrapped.

    Now of course, they allow far far larger exchange message stores - just to increase the possibility of "unrecoverable database error".

    I *do* know of an Exchange consultancy who lost their exchange mail for 100+ users - for an entire WEEK. Scary. Thats business-killing stuff. And they're consultants - not some users. Scary.

    So how have they chosen to address this in E12. What do you get for your upgrade money ?

    Well:

    * upgraded message store. No. Actually still JET

    * active/active clustering. Ah. No. Whilst its supposed to work now, its actually been removed from E12 completely.

    Nice.

    Less reliable, more expensive, unreliable and badly architected. Must be Microsoft!

    But hey - E12 does bring us far far bigger versions of word and Excel with "collaboration" built in. Deep joy.

    Wonder how many users have upgraded to Exchange 2003 ? Is it more than 15% of the exchange base ? Or are most of them still on 5.5.. ?

    ---* Bill

  1. 12  Simon Barratt http://apps.fmc.com/blog.nsf | 12/6/2005 3:05:36 PM

    Just had the misfotune of proving out the theory being discussed here!

    { Link }

    Thankfully clustered servers and per user mailboxes minimised the impact!

  1. 13  Nathan T. Freeman  | 12/7/2005 3:05:13 AM

    Interesting point, Bill. MS touting the increased user/server count in E12, while maintaining the same database structure on the server in a single-copy store, is simply going to increase the likelihood of catastrophic failure, and the impact thereof.

  1. 14  Darren http://www.dadams.co.uk | 12/7/2005 11:14:41 AM

    @11 and @13 - the analogy I used recently was "having a turbo fitted to your car without solving the problem affecting the brakes".

  1. 15  Mike Robinson http://www.invcs.com | 12/7/2005 6:22:41 PM

    But WAIT! The storage group/single store concept is actually genius! Don't you know how many Exchange real-time backup vendors have cropped up to provide transaction based recovery to storage group dbs? Whenever you buy Exchange it's mandtory to buy a recovery tool (if you want to keep your hair and your job). The Domino approach of being so darn rock solid is bad for ISVs in this niche.

    Well this is actually tongue and cheek- however rooted in truth :) so I'll stop right there...

  1. 16  Mike Lazar  | 12/8/2005 9:28:24 AM

    Piping in late here, but if the single-copy store was the better choice, we'd all be running it. Again, Domino offers you the flexibility to do it or not. The overwhelming choice has always been individual mailboxes. It's more flexible, easier to manage, and has less risk. Considering you can't really put less than 72 GB on a drive now anyway, the days of trying to conserve disk space are in the past.