Microsoft cancels support for single instance storage

Microsoft has made major changes in some of the underlying data structures for Exchange Server 2010, and these significant changes will have a greater impact on subsequent storage requirements and deployments for Exchange Server 2010.

The biggest change Microsoft has made is to remove the single instance store (Single-instance storage,sis). In previous versions, if a message was forwarded to multiple recipients, only one copy of the message would be stored in the mailbox database. The user will receive a pointer to this single copy rather than a full copy of the copy.

So, since Microsoft has canceled support for single instance storage, it means that the same message is sent to multiple recipients, and each recipient receives a copy of the entity message. From a storage space planning perspective, the impact of this huge change on planning depends largely on the number of messages with attachments.

Text or HTML-formatted messages are generally very small, so they have little impact on the storage space plan, and Microsoft has automated compression mechanisms for these messages to further reduce the impact. However, if your environment always has users sending messages with large attachments to multiple recipients, these messages will have a significant impact on the incremental database. The goal of Microsoft's redesign of the database's underlying architecture is to reduce the I/O load renewal of the database. So, Microsoft chose not to compress mail attachments this time, in order to save the additional cost of storage I/O during the compression/decompression process.

It may seem odd that, once upon a time, storage management has been doing a bit of data reduction, such as data de-duplication, but why Microsoft has removed the data reduction feature in Exchange Server 2010. Since Microsoft has abandoned the use of single instance storage for Exchange mailbox databases, the database will work more efficiently, and Microsoft claims that Exchange Server 2010 's database I/O load requirements have decreased by about 70%.

Another common way to keep your Exchange Server 2010 mailbox database from becoming too big is to use a mailbox limit. The mailbox limit feature prevents the size of a mailbox from exceeding the preset size. In Exchange Server 2010, the mailbox quota functionality is almost identical to the previous version, except for one point. Exchange Server 2010 introduces a concept called an archive mailbox (which we'll discuss later). If a user has an archived mailbox, the mailbox limit does not count the contents of the archived mailboxes when calculating how much of the underlying space the user is using. Exchange also allows you to limit the size of your archived mailboxes with additional quota allocations.

Mailbox limit This feature is a sufficiently proven method to limit the amount of data stored too quickly. But Microsoft has been encouraging companies to use low-cost storage systems instead of using mailbox quotas to save costs. The starting point is that businesses can avoid spending too much on expensive storage systems and solutions while keeping mailbox data growing.

The recommended use of low-cost storage systems is not only based on the cost of simple storage. Many companies are forced to set very strict quota policies on mailboxes so that the corresponding mailbox users have to delete some important messages. Obviously, if you use a cheap storage system, the enterprise can open up the mailbox limit, even do not apply the limit.

Before, it seemed unheard of to use the lowest-end low-cost storage System in an Exchange Server environment, but the reduction in the I/O load requirements in this Exchange Server 2010 makes the storage options such as SATA hard disks acceptable. and Exchange Server 2010 has a very flexible requirement for underlying storage that can use direct-attached storage (direct-attached Storage,das) or storage area Network SAN devices, You can even use storage that is connected through an iSCSI protocol. However, Microsoft does not support storage in Exchange Server that must be mapped into a network letter to access data, such as NAS. Therefore, Exchange server does not support storing mailbox databases in NAS unless the NAS supports iSCSI protocol access.

(Responsible editor: The good of the Legacy)