Direct Attached Storage (DAS)

DAS is a digital storage system directly attached to a server or workstation, without a storage network in between. For example, DAS transports include Serial Attached SCSI (SAS), Serial Attached ATA.

Storage Area Network (SAN): iSCSI

SANis an architecture to attach remote computer storage devices (such as disk arrays and tape libraries to servers in such a way that the devices appear as locally attached to the operating system (for example, block storage). iSCSI SAN's encapsulate SCSI commands within Internet Protocol (IP) packets and use standard networking infrastructure as the storage transport (for example, ethernet).

Don't share physical disks backing Exchange data with other applications.

Use dedicated storage networks.

Use multiple network paths for stand-alone configurations.

Storage Area Network (SAN): Fibre Channel (FC)

(SAN) is an architecture to attach remote computer storage devices (such as disk arrays and tape libraries to servers in such a way that the devices appear as locally attached to the operating system (for example, block storage). Fibre Channel SANs encapsulate SCSI commands within FC packets and generally utilize specialized Fibre Channel networks as the storage transport.

Don't share physical disks backing Exchange data with other applications.

Use multiple FC network paths for stand-alone configurations.

Follow storage vendor's best practices for tuning FC Host Bus Adapters (HBAs). For example, Queue Depth/Queue Target.

SATA

SATA is a serial interface for Advanced Technology Attachment (ATA) and integrated device electronics (IDE) disks. SATA disks are available in a variety of form factors, speeds, and capacities.

In general, choose SATA disks for Exchange 2010 Mailbox storage when you have the following design requirements:

• High capacity
  
• Moderate performance
  
• Moderate power utilization
  

Requires battery backed caching array controller for optimal data reliability and I/O performance. Physical disk-write caching must be disabled when used without an uninterruptable power supply (UPS). When considering SATA disks, we suggest considering "Enterprise class" SATA disks which generally have better heat, vibration, and reliability characteristics.

SAS

SAS is a serial interface for Small Computer System Interface disks. SAS disks are available in a variety of form factors, speeds, and capacities.

In general, choose SAS disks for Exchange 2010 Mailbox storage when you have the following design requirements: 

• Moderate capacity
  
• High performance
  
• Moderate power utilization .
  

Physical disk-write caching must be disabled when used without an UPS.

Fibre Channel (FC)

Fibre Channel (FC) is an electrical interface used to connect disks to Fibre Channel-based storage arrays (SANs). FC disks are available in a variety of speeds and capacities.

In general, choose FC disks fore Exchange 2010 Mailbox storage when you have the following design requirements:

• Moderate capacity
  
• High performance
  
• SAN connectivity
  

Physical disk-write caching must be disabled when used without an UPS.

SSD (Flash Disk)

A solid-state drive (SSD) is a data storage device that uses solid-state memory to store persistent data. An SSD emulates a hard disk drive interface. SSD disks are available in a variety of, speeds (different I/O performance capabilities) and capacities.

In general, choose SSD disks for Exchange 2010 Mailbox storage when you have the following design requirements:

• Low capacity
  
• Extremely high performance .
  

Physical disk-write caching must be disabled when used without an UPS.

In general, Exchange 2010 Mailbox doesn't require the performance characteristics of SSD storage.

OS/System/Pagefile Volume

All RAID types supported.

Best Practice: RAID 1/10

All RAID types supported.

Best Practice: RAID 1/10

Exchange Mailbox Database File (ED Volume

All RAID types supported.

Best Practice: 5.4K/7.2K Disks = RAID1/10 only

All RAID types supported.

JBOD/Raidless supported (3 or more database copies)

Best Practice: 5.4K/7.2K Disks = RAID1/10 only or JBOD

Best Practice: When lagged, database copies should have either two or more lagged copies or lagged copies should be protected with RAID.

Exchange Mailbox Database Log Volume

All RAID types supported.

Best Practice = RAID1/10

All RAID types supported.

JBOD/Raidless supported (3 or more database copies)

Best Practice = RAID1/10

Best Practice: When lagged database copies should have either two or more lagged copies or lagged copies should be protected with RAID.

Disk Array RAID Stripe Size (kb)*

The stripe size is the unit of data distribution within a RAID set.

Best Practice: 256KB or greater. Follow storage vendor best practices.

Storage Array Cache Settings

The cache settings provided by a battery-backed caching array controller.

Best Practice: 75 percent write cache and 25 percent read cache (battery-backed cache). Follow storage vendor best practices.

Physical Disk Write Caching

The settings for the cache are on each individual disk.

Supported: Physical disk write caching must be disabled when used without a UPS.

File Placement: Database/log isolation

Database/log isolation refers to placing the database file and logs from the same Mailbox database on to different volumes backed by different physical disks.

Best Practice: For recoverability, move database file (.edb) and logs from the same database to different volumes backed by different physical disks.

Isolation of logs and databases isn't required.

File Placement: Database files/volume

Database files/volume refers to how you distribute Database files within or across disk volumes.

Best Practice: Based on your backup methodology.

Supported: When using JBOD, divide a single disk in to two volumes (one for database, one for log stream).

Best Practice: When using JBOD, single database per log per volume.

File Placement: Log streams/volume

Log streams/volume refers to how you distribute database log files within or across disk volumes.

Best Practice: Based on your backup methodology.

Supported: When using JBOD, divide a single disk in to two volumes (one for database, one for log stream).

Best Practice: When using JBOD, single database per log per volume.

Database size

The on disk database file size (.edb)

Supported: Approximately 16 TB

Best Practice:

• 100GB or less
  
• Provision for 120% of calculated maximum database size
  

Supported: Approximately 16 TB

Best Practice:

• 2 TB or less
  
• Provision for 120% of calculated maximum database size
  

Log truncation method

The process for truncating and deleting old database log files. There are two mechanisms:

• Circular logging, in which Exchange deletes the logs
  
• Log truncation, which occurs after a successful Full/Incremental VSS backup
  

Best Practice:

• Use backups for log truncation (e.g., circular logging disabled)
  
• Provision for three days of log generation capacity.
  

Best Practice:

• Enable circular logging for deployments which use Exchange 2010 data protection features.
  
• Provision for three days beyond replay lag setting of log generation capacity.
  

Basic disk

A disk initialized for basic storage is called a basic disk. A basic disk contains basic volumes, such as primary partitions, extended partitions, and logical drives.

Supported

Best Practice: Use basic disks

Supported

Best Practice: Use basic disks

Dynamic disk

A disk initialized for dynamic storage is called a dynamic disk. A dynamic disk contains dynamic volumes, such as simple volumes, spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes.

Supported

Supported

GUID Partition Table (GPT)

GPT is a disk architecture that expands on the older Master Boot Record (MBR) partitioning scheme. The maximum NTFS formatted partition size is 256 TB.

Supported

Best Practice:

Use GPT partitions

Supported

Best Practice:

Use GPT partitions

Master Boot Record (MBR)

A master boot record (MBR), or partition sector, is the 512-byte boot sector that is the first sector ("LBA Sector 0") of a partitioned data storage device such as a hard disk. The maximum NTFS formatted partition size is 2 TB.

Supported

Supported

Partition alignment

Partition alignment refers to aligning partitions on sector boundaries for optimal performance.

Windows Server 2008 default: 1 MB

Windows Server 2008 default: 1 MB

Volume path

Volume path refers to how a volume is accessed.

Supported:

Drive letter or mount Point

Best Practice:

Mount point host volume must be RAID'ed.

Supported:

Drive letter or mount point

Best Practice: Mount point host volume must be RAID'ed.

File system

File system is a method for storing and organizing computer files and the data they contain to make it easy to find and access them.

Supported:

NTFS support only

Supported:

NTFS support only

NTFS defragmentation

NTFS defragmentation is a process that reduces the amount of fragmentation in Windows file systems. It does this by physically organizing the contents of the disk to store the pieces of each file close together and contiguously.

Not required and not recommended.

Not required and not recommended.

NTFS allocation unit size

NTFS allocation unit size represents the smallest amount of disk space that can be allocated to hold a file.

Supported:

All allocation unit sizes.

Best Practice:

64KB for both .edb and log volumes

Supported:

All allocation unit sizes.

Best Practice:

64KB for both .edb and log volumes

NTFS compression

NTFS compression is the process of reducing the actual size of a file stored on the hard disk.

Not supported for Exchange database/log files

Not supported for Exchange database/log files

NTFS Encrypted File System (EFS)

EFS enables users to encrypt individual files, folders, or entire data drives. Because EFS provides strong encryption through industry-standard algorithms and public key cryptography, encrypted files are confidential even if an attacker bypasses system security.

Not supported for Exchange database/log files

Not supported for Exchange database/log files

Windows Bitlocker (volume encryption)

Windows BitLocker is a data protection feature in Windows Server 2008. BitLocker protects against data theft or exposure on computers that are lost or stolen, and it offers more secure data deletion when computers are decommissioned.

Supported for all Exchange database and log files

Supported for all Exchange database and log files