Data Storage: Microsoft Seeks to Refute Top 10 Exchange Storage Myths
Microsoft Seeks to Refute Top 10 Exchange Storage Myths
by Chris Preimesberger
Myth No. 1: Exchange requires expensive, high-performance storage.
Exchange 2010 now enables users to implement large, low-cost mailboxes. It performs well on less-expensive disks and supports a range of storage options.
Myth No. 2: Exchange 2010 doesnt support SANs (storage area networks).
Exchange 2010 still doesn't support NAS (network-attached storage), but it does support a large range of storage options, including SAN and DAS (direct-attached storage). Depending on the high-availability model, storage can be configured using RAID or RAID-less (JBOD) storage. Different customers will require different solutions based on their requirements, but everyone has the ability to deploy large mailboxes at low cost.
Myth No. 3: I already have a SAN, so it doesnt make sense to implement DAS.
This one is not really a myth, but it is often misunderstood. SAN deployment may make sense for users as long as they are able to deploy large mailboxes at low cost. Remember that Exchange supports a range of storage options, including SAN and DAS. If you want to take advantage of multiple independent copies of databases, then consider the full cost of your storage solution.
Myth No. 4: JBOD configurations arent practical because the reseed process after a disk failure takes too long, and this generates too much operational overhead.
Microsoft IT uses a JBOD configuration successfully, and it can be a very low-cost solution. However, a level of operational maturity is required to manage the environment appropriately. There are a multitude of factors that can affect seeding throughput rates. Internally, Microsoft sees between 35GB-70GB/hour in its JBOD architecture.
Myth No. 5: Large mailboxes perform badly with Outlook.
Exchange 2010 supports up to 100,000 items per folder, up from 20,000 in Exchange 2007. In addition, the Outlook 2007 SP1 Feb09 update, Outlook 2007 SP2 and Outlook 2010 provide good performance for Cached Exchange Mode for mailboxes up to 10GB in size, and even larger (25GB) using faster disks, such as 7.2K drives or SSD. The Exchange 2010 store was improved to support very large mailboxes (100GB+) in online mode and with OWA. You can also use the Exchange 2010 personal archive to reduce mailbox size for Cached Exchange Mode clients.
Myth No. 6: When I migrate to Exchange 2010, my database size will explode because Exchange 2010 doesnt have SIS (single instance storage).
Exchange storage planning guidance has always dictated designing the storage without SIS in mind. SIS reduces Exchange Server's ability to do sequential data access, and the changes made help to provide the 70 percent I/O reduction. Exchange 2010 does provide 20 percent database compression for HTML/plain text messages.
Myth No. 7: My Exchange guy knows nothing about storage; it needs to be managed by the storage experts. Less expensive storage is too hard and time-consuming/expensive to manage.
Microsoft knows from the many organizations it has talked to who are using DAS (including Microsoft's own deployment) that they have not needed any additional people to manage less expensive Exchange storage, nor have they increased their operational costs. When storage is expensive, you can spend a lot of time and resources optimizing for your storage investment. Using less-expensive storage enables you to take a conservative approach and allows you to overprovision. The storage is then never touched except for firmware/driver updates or disk failures. You can use server management staff to manage the storage, since the tasks are very similar with driver and firmware updates.
Myth No. 8: I cant back up large Exchange databases.
With the ability to have multiple copies of each database, along with features such as single recovery and lagged copy support, you might not need to use traditional backups. You also can look at reducing the number of backups to weekly or bimonthly full backups, you can back up from passive database copies, and you can use DPM "express" backups to save space.
Myth No. 9: We need a third-party archiving package because Exchange data needs expensive storage, and we need to put archived data on less expensive storage.
You can put all Exchange data on less expensive storage, not just the archive data. Co-locate hot and cold data to efficiently utilize large low-cost disks and simplify management by using a single storage type.
Myth No. 10: All Exchange storage designs must follow the Exchange Mailbox Role Requirements Calculator verbatim, otherwise they will not be supported.
The Exchange Mailbox Role Requirements Calculator (Exchange 2010/Exchange 2007) provides design guidelines, but does not have anything to do with supportability. The Exchange Solution Reviewed Program (ESRP) also has information from Microsoft's storage partners.