TenBrink Tech Technology | Life

MSG 313 – Exchange 2007 Storage Changes

Just got out of an interesting briefing this morning on the storage changes in Exchange 2007. Here are some of the highlights.

Database Counts

• 50 Storage Group Max/Server
• 50 Databases Max/Server
• 5 Database/Storage Group
• Recommend 1 Database to 1 Storage Group mapping. Improves IO coalesence.

Flexible databases

• Databases can be mounted in parallel.
• Databases can be mounted on any server.

No more STM, ExIFS is gone, no more kernel mode drivers.

New: Continuous Replication

• 2 modes: Local (LCR) and Cluster (CCR)
• CCR: create clusters without shared storage infrastructure.
• Save costs by not being on the SAN.

Content Indexing: On by default now to support Office/WDS search features. Runs as a background process and consumes about 5% of database size for index.

Things that stick around: dual-phase commits, random access to the database with fixed page size, ability to coalesce IO operations from RAM to disk.

Things new to 2007 that help those old things: more use of memory (64-bit technology breaks the virtual memory barriers) - nearly unlimited (somewhere in the low TB of RAM).

Database Changes

• 8kb page size
• More use of RAM (900 MB limit in Ex03, > 2 GB cache in Ex07)
• More storage groups = more memory checkpoint depth = more IO coalescence.
• IO Coalesence: 2003 4KB-64KB, 2007 8KB to 1MB,

Transaction Logging

• Generations in the billions
• Logs go from 5MB to 1MB to support continuous replication.
• Improved checkpoint recoveries from single-bit errors.

Value gains

• Increase storage density - use fewer drives & larger drives.
• Diminished reliance on SAN and high speed storage
• 10K RPM drives are ok (15K were required with Ex03).
• High speed not required (iScsi applications instead of FC requirement).
• Goal: reduce cost per mailbox, per GB of storage.

The only downsides to this is some of the same restirctions still remain. They still recommend keeping folder item counts under 5,000. That is an increasingly hard task to do, even with email archiving. MSFT is selling Email Lifecycle Management and rules as the solution to help manage this restriction.