Hi We have a sister company that is moving from Exchange 2003 to 2007 SP1. They will have 5000 users spread over 50 databases -i.e. 100 users/database. We need to work out which users will be on which database. We could: i) Allocate DB's by department to utilise Single Instance Storage (SIS)ii) Allocate users randomly to each DB (e.g. by first letter of name) There is a good article here on SIS: http://msexchangeteam.com/archive/2008/02/08/448095.aspx What confuses me is that is states: "SIS has also diminished in importance because of the way storage hardware has evolved. Over the past 10 years, the capacity of disk drives has risen sharply, but IO performance has remained flat, leaving most Exchange customers constrained by disk IO rather than disk space. In 1996, a typical disk was 10GB in size, and delivered about 100 IOPS; or about 10 IOPS/GB. Today, a typical disk is 500 GB and delivers about 100 IOPS; or about 0.2 IOPS/GB. The IOPS per GB has dropped 50 fold. Single instancing is fundamentally about saving disk space at the expense of increased IOs. So, while trading IOs to save space was a good strategy 10 years ago, today a focus on IO reduction makes more sense." Question 1: How can we focus on IO reduction? The article also states: "In Exchange 2007, attachments are single instanced, but message bodies are not. This behavior does not apply to the move mailbox operation, so when you transition to Exchange 2007 from Exchange 2000 or Exchange 2003, single instance storage is maintained for both message bodies and attachments, as long as: The mailboxes being moved belong to the same source database and the same destination database You are using a "transition" approach rather than a "migration" approach for your upgrade" Question 2: So basically, SIS changes in Exchange 2007 so that only attachments use SIS, not message bodies? But this wouldnt have much effect would it since message bodies tend to be quite small anyway? Question3: We may look to increase mailbox quotas for certain departments to over 1GB this year (e.g. for people who send a lot of graphic attachments). I assume for cases such as this, placing them in the same store would make sense to take advantage of SIS?

On Sun, 28 Mar 2010 23:56:15 +0000, Sheen1990 wrote:>>>Hi >>We have a sister company that is moving from Exchange 2003 to 2007 SP1. They will have 5000 users spread over 50 databases -i.e. 100 users/database. >>We need to work out which users will be on which database. We could: >>i) Allocate DB's by department to utilise Single Instance Storage (SIS)ii) Allocate users randomly to each DB (e.g. by first letter of name) Use whatever makes sense to you. Keeping the databases about the samesize and with the same number of users usualy works best. Puttingeveryone in the same department in the same database means they'll allbe off-line if there's a problem with that one database.Using the 1st letter of a name isn't random. You'll wind up with lotsmore mailboxes in some databases than others. [ snip ]>Question 1: How can we focus on IO reduction?By moving to Exchange 2007 or 2010. The savings in I/O from largerdatabase page size and larger caches is substantial (and much greaterin 2010).>The article also states: >>"In Exchange 2007, attachments are single instanced, but message bodies are not. >>This behavior does not apply to the move mailbox operation, so when you transition to Exchange 2007 from Exchange 2000 or Exchange 2003, single instance storage is maintained for both message bodies and attachments, as long as: >>The mailboxes being moved belong to the same source database and the same destination database You are using a "transition" approach rather than a "migration" approach for your upgrade" >>Question 2: So basically, SIS changes in Exchange 2007 so that only attachments use SIS, not message bodies? That's correct.>But this wouldnt have much effect would it since message bodies tend to be quite small anyway? I think you have that turned around. There's little savings to be hadby applying SIS to message bodies. Storage benefits from SIS appliedto the larger attachments.>Question3: We may look to increase mailbox quotas for certain departments to over 1GB this year (e.g. for people who send a lot of graphic attachments). I assume for cases such as this, placing them in the same store would make sense to take advantage of SIS? Only if they're using e-mail to transfer files among themselves. Inthat case it would make more sense to use a file server or sharepoint.Neither of those has to deal with overhead of content conversion.---Rich MatheisenMCSE+I, Exchange MVP--- Rich Matheisen MCSE+I, Exchange MVP