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Optimize Mailbox Layout: It is best to limit the no. of critical mail
stores/mailboxes per server. Encourage separation of mail stores on
separate servers. Separate Logs and mail stores on different
volumes. Here are some of the database volume characteristics with
I/O patterns:
Jet database (.edb): This is used to hold all data submitted by
MAPI clients. Typical I/O profile is 4K random I/O with read write
mix.
Streaming database (.stm): Stores attachments.
profile is 8K read/write with a mix of sequential and random load.
Transaction Log Files (.log): All changes to database are first
committed to this file. This volume has 100% sequential writes
during normal operations and 100 percent sequential reads
during recovery.
It is better to use MS Basic disks (this is also supported by iSCSI
S/W initiator) with NTFS partition and allocation unit of 4K. It
must be noted that diskpart can be used to extend partition and
file system size automatically and online.
StorTrends iTX stack with a myriad of features aimed at performance
monitoring and tuning offers the best storage solution. StorTrends iTX stack
also has built in automatic performance tuning, load balancing and I/O
plugging capabilities enabling it to yield extremely high I/O performance. In
such deployments, to guard against data loss, snapshots are extensively
used. The special Redirect on write algorithm used by iTX stack gives it a
differentiating edge over the much used Copy on write architectures
employed by competition. In other architectures, with every new snapshot
taken the metadata writes increase leading to drop of I/O performance. The
ability to create multiple snapshots in iTX using delta snap table layout
ensures that there is no additional overhead incurred when many snapshots
are active.
Refer to MS Guidelines:
See the following Microsoft documentation for network storage-based
Exchange Mailstore and replication best practices and support criteria:
TcpAckFrequency = 1 for each iSCSI connection:
http://support.microsoft.com/kb/328890.
Deployment Guidelines for Data Replication:
http://www.microsoft.com/technet/prodtechnol/exchange/guides/
E2k3DataRepl/bedf62a9-dff7-49a8-bd27-b2f1c46d5651.mspx
Multi-site data replication support for Exchange:
http://support.microsoft.com/?kbid=895847
Typical I/O
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