Two-Minute Drill

Understanding RAID and SVM Concepts

q	RAID 0 (striping) does not provide fault tolerance, but it can provide performance improvement by performing simultaneous read/write on multiple stripes.
q	RAID 1 and RAID 5 provide fault tolerance by mirroring and parity, respectively.
q	RAID 0 and RAID 1 both require a minimum of two disks, whereas RAID 5 requires a minimum of three disks.
q	A hot spare is a slice of data that stands ready to be substituted for a failed data slice. A hot spare can be assigned to one or more hot spare pools.
q	A hot spare pool is an ordered list of hot spares, and it can serve one or more RAID 1 and RAID 5 volumes.
q	SVM can mange a maximum of 8192 logical volumes per disk set, but the default configuration is 128 logical volumes per disk set.
q	SVM allows you to divide a disk slice (or a volume) into as many divisions as you want, and each division is called a soft partition.
q	A stripe volume contains equally sized data segments across multiple components (slices or soft partitions), and the data is written in parallel on multiple components. Therefore, you cannot change the component size (interlace value) dynamically.
q	A concatenation volume writes data to components sequentially—that is, it fills the first component first before moving to the next component.
q	You can add new components to a stripe volume, and then it is called a concatenated volume.
q	In SVM, the default read and write policies are round-robin read and parallel write.

Creating State Databases and Mirrors

q	You can use either the SVM GUI or the metadb command to create, delete, or check the status of a state database.
q	When a state database is lost, the majority consensus algorithm is run to determine which of the remaining replicas contain the valid data. This imposes the requirement that you must create at least three replicas of the state database.
q	The default size for a state database replica in SVM is 8192 blocks (4MB).
q	To build a mirror (RAID 1 volume), you can create a submirror with the metainit command, and you must attach the second submirror to the mirror with the metattach command.