Think 'big picture' for SATA Exchange storage
By Brett Cooper
A SearchStorage.com reader recently asked: Should SATA be used for small Exchange environments (about 50 people or less)?
More and more companies are trying to save money by using less-expensive disk where appropriate. SATA, or serial ATA, disk has become a popular choice, as it offers reasonable performance at a fairly affordable price. SATA is a relatively new standard for connecting hard drives into computer systems and its best usage is still being debated throughout the storage world.
Here are some important considerations if you are thinking about deploying SATA for storing Exchange data:
- 1. Performance to be at a certain level
- 2. Availability to be at a certain level
- 3. The environment to be blueprinted and supported:
- a) Exchange Server specifics:
- Number of storage groups in the Exchange server, with only 50 users, I think that you will be OK with one storage group
- Number of mail accounts: 50
- Number of mails sent/received per day: Let's say, 50 sent and 20 received per user or 3,500 e-mails per day
- Attachments included: Let's say, 5% of the e-mail sent will include attachments, or some 175 per day with an average of a 1 MB attachment
- Calendaring -- Folder usage
- Total storage size allotted for each user of 100 MB, or a total of 50 GB of storage plus 10% for wiggle room, or 55 GB of total storage for the Exchange server
- b) Data protection/availability strategy for the environment: If you are asking about running the Exchange server on a single SATA drive, I would say, don't even think about it, as a single drive failure will cost you recovery and outage time and your users will most likely hang you from the closest possible location, but if you are talking about a RAID group of SATA disks and a mirror with a tape backup or archive, then you should be ok from a data protection space.
- c) Anything else that needs to be known from a performance or configuration perspective? Will the system be used for other things? If so, then you will need to size the environment accordingly.
With all of the above in mind, you should look to your budgetary or cost goals for the project. Internal server storage will always be the least expensive, but will have the highest management costs from a personnel perspective. You could easily put SATA disks in your server and create a RAID array, keep one disk as a hot spare and provide the required storage space and performance needs of the environment. SATA technology disks usually spin slower than their Fibre Channel (FC) cousins and also don't meet the same stringent performance and availability MTBF numbers that you would expect from a more expensive FC drive. You have to ask yourself whether the trade off is worth it?
Another option to consider is separating the storage from the server, so you have a highly available storage array from one of the larger vendors using SATA disks. Almost all of the major storage enclosure manufacturers will offer you SATA disks with a FC or iSCSI connection for your Exchange environment. This provides stable storage with snapshot capabilities that integrate into Exchange. Every major manufacturer that offers SATA disks in their enclosures will support Exchange, but they will try to convince you to buy a dual-controller configuration to maintain the highest levels of availability. A single-controller configuration will be more likely to experience data loss than a dual-controller configuration. As you read this, you are probably thinking that the SATA drive isn't the issue, the issue is in the rest of the infrastructure around the SATA drive.
The point is: Don't just focus on the disk interface, focus on the complete picture for the infrastructure.
For more information:
Brett Cooper is the director of marketing for Intermine Inc.
26 Jan 2006
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