eWeek is "reporting" a "story" today based on Microsoft's rebuttals to the "Top 10 Exchange storage myths" (forgive my air quotes on all of this, but it's hard to believe eWeek considers this news).  Their source is the Exchange team blog, and I think it's a clever blog entry.  

I just don't like the revisionist history in myth #6.  There, Microsoft says:

Myth #6: When I migrate to Exchange 2010 my database size will explode because Exchange 2010 doesn't have single instance storage (SIS).

Reality: Exchange storage planning guidance has always dictated designing the storage without SIS in mind. SIS reduces Exchange Server's ability to do sequential data access, and the changes made help to provide the 70% IO reduction.
It's funny that you say that now, Exchange team.  Because for the prior thirteen years, you've used Exchange's SIS as a selling point -- in your classic weakness-as-strength approach -- over Domino's single mailbox per user design.  Now, you've done copied us.  Amazing.

Here's an old Microsoft slide from a competitive presentation (sorry for black and white):

Image:Microsoft Exchange storage revisionist history

Or a blog in 2005 where the single instance store was described as "fairly powerful".

Now, most of you who know email knew that the Exchange single instance store was a pretty bad architecture.  It had shades of old cc:Mail's Achilles heel -- one file equals one point for problems.  Corrupt that file, have to restore an individual message, etc...it was not ideal.  Microsoft came up with some pretty good workarounds for deficiencies over the years, but it was still a single copy of an email, in a large, fragmented, always open file, with no data redundancy, and a single point of failure.

At least now they are admitting it wasn't a useful architecture and didn't save any disk space.  In fact whenever we looked at like for like, Exchange environments always had about the same amount of disk space per user, so charts like the one above were completely bogus.  Now the story has changed, and of course everything in Exchange 2010 is wonderful and the best way to go.

Which makes me continue to wonder why six months after its release, Microsoft still hasn't updated Exchange Online to offer Exchange 2010.

eWeek's reporter also got the basics wrong, reporting that "staple of enterprise IT systems around the world since 1993", when it first shipped in 1996 in a version that was limited to 16GB -- for the entire mail server.  At least he got one part of the mythology right: "Microsoft Exchange....has a reputation of being a beast to handle. In fact, eWEEK has quoted a few IT managers using that exact term--and worse--when describing their experiences with the venerable e-mail storage system."

Link: eWeek: Microsoft Seeks to Refute Top 10 Exchange Storage Myths >

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