You need info about RAID. It's that simple. In the world of storage, RAID (redundant array of independent disks) is a major topic. Whether you are a RAID rookie or you're trying to optimize performance of a huge array, you'll learn something here. This Fast Guide offers RAID news, expert technical advice and tips.
RAID-53: RAID by any other name
The first thing to understand about RAID-53 is that it has the wrong name. A better name for it would probably be "RAID-03," as it involves, in essence, striping (RAID-0) a series of RAID-3 (striping with a separate parity disk) arrays without additional parity.
RAID-50: RAID-5 with suspenders
Like the other double-digit RAID levels, RAID-50 is a combination of two basic RAID techniques. It combines striping (RAID-0) with independent data disks with distributed parity (RAID-5).
The essential RAID primer
Always wanted to be a RAID know-it-all? Take a look at part one of Evan Marcus' RAID primer where he covers the various levels of RAID. Each level's description is concise and to the point. Bookmark Evan's primer and brush up on the RAID.
RAID-2 isn't being used anymore
Even though you don't see RAID-2 being used all that much anymore, according to our expert Norbert Haag, and RAID-2 literature, there is a minimum number of drives when setting up a RAID-2 system. Hint: It's less than 10.
RAID: How safe is your data?
RAID, in its current designs, can handle a single-disk failure gracefully. However, in the case of a double-disk failure in a given RAID volume the results can be disastrous.
RAID groups and parity groups
RAID groups can contain single or multiple parity groups. You can think of the RAID group as the actual RAID container for data protection, and the parity group as a partition of that container.
Migrating from DAS to a SAN
As for flexibility and performance, you can configure different RAID types within the arrays to match the applications requirements. RAID-1 or RAID-10 is best for log file storage, and RAID-5 can house database-type storage.
Data compatibility between ATA and FC
ATA arrays may be configured the same as FC arrays (number of drives in the RAID group, stripe size and parity protection) or may be completely different, but that doesn't matter when the data is accessed from the storage controller by a server.
Alternatives to software mirroring
The usual "ghosting" approach presents support challenges with RAID disks, making that solution unreliable in the current context. Mirroring does have its limitations, with the most obvious being the risk of corruption to two images instead of one.
Maximum number of drives in a RAID-5 set
The number of maximum number of drives in a RAID-5 set will vary by vendor implementation according to expert Greg Schulz. Take a peek at this Ask the Expert Q&A and find out more about drives in a RAID-5 set.
Calculating space for parity in RAID-5
How do you determine how much space parity will consume in RAID-5? For instance, if I have a RAID-5 with 10 146 GB drives, what is the percent factor of space used for parity?
How to select disk drives for DBMS
Database management systems (DBMS) put heavy demands on storage. If you have the opportunity to select disks specifically for a DBMS system, you can maximize your performance by making the right choices.
Advanced RAID functions
Part one introduced you to hot swapping, online capacity expansion and online RAID level migration. Part two exposes you to N-way mirroring, splitting and hiding and more.
Expanding a four-disk RAID array
What do you do when your RAID 5 array is running out of room? Can you replace each drive one at a time and rebuild the array? A lot depends on which vendor you're using.
Tech Report: Flexible RAID arrays
Storage analyst Jerome M. Wendt's "Tech Report" takes look at RAID arrays and says the key to good management is "selecting the right mix of disks and RAID levels."
RAID: Do you speak geek?
Think you know RAID? Take our quick quiz and see how you measure up on our RAID geek-o-meter. How many can you guess without peeking?
SAN School -- Lesson 2: SAN building blocks
Join Christopher Poelker, co-author, "Storage Area Networks for Dummies" for a webcast on SANs. Chris defines SAN components and their uses as well as storage arrays and RAID.
Although EMC looks to TwinStrata technology to turn the cloud into a storage tier from inside a SAN, one customer proves CloudArray has value without a separate SAN for primary, backup and disaster recovery storage.