A Comparison of Different Kinds of Storagesets

[Eduardo70_86]

hi

Im working with a group of alpha servers and I most configure the storage works, I research about the differents kinds of storage set like: RAIDset, Stripeset, Mirrorset, and StripeMirrorset. I found a lot about these stoagesets but I really dont undestand very good what are the difference between the storagesets , and how work eaveryone , so someone can explain to me how does a chose?

thank you.

[Sheldon Smith]

It sounds like you are working with a StorageWorks HSG / EMA array. The differences of the storagesets are reliability, capacity and write performance.

A Mirrorset of two drives duplicates the contents of one with the other. If any one fails, you still have all your data. Everything is then duplicated to a hot spare.
High reliability, high performance (two physical writes for every logical write).
Low capacity (you need double the physical storage).

A Stripeset of two or more drives acts like one big drive. If any one fails, you have LOST all your data.
High performance (one physical write for every logical write, a large logical write may be quickly completed across multiple drives).
Good capacity (all disks contribute to the storage).
No reliability (as mentioned above, if any disk fails, the Stripeset is no good).

A StripeMirrorset combines a Mirrorset and a Stripeset. Stripeset performance with Mirrorset reliability. Mirrorset capacity (again you need double the physical storage).

A RAIDset of three or more drives uses computer logic to generate parity information on one of the drives (an over-simplification). If any one fails, the remainer are used to calculate the missing data to a hot spare.
High reliability, moderate performance (a logical write may require reading from the other disks to be able to calculate the new parity which then also needs to be written). Good capacity (all disks but one contribute to the storage).

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[Eduardo70_86]

thank you very  much :D