HP ProLiant SL170s ISS Technology Update, Volume 9 Number 5 - Page 5

Figure 3-1. Strips and stripes for a typical RAID 5 logical drive A stripe, on the other hand, is the collection of one set of strips across the physical drives in a logical drive. A stripe's size is not configured. It is a product of the strip size, the number of physical drives in the logical drive, and the RAID level. In Figure 3-1, a stripe is represented by each color band across the physical drive set. If the strip size in this logical drive is 256 KiB, then the stripe size is three times that, or 768 KiB. The parity strip -- represented by Ap, Bp, etc. in Figure 3-1 -- is not considered part of the stripe's size although it is part of the structure. The stripe size for a RAID-5 and RAID-6 array is the same, even though there is twice as much parity data. Changing terms to strip size HP Smart Array utilities have traditionally used the term stripe size as a configuration parameter when, in terms of standard RAID definitions, it's the strip size that's actually being configured. In order to differentiate between the two, HP documentation has sometimes referred to the RAID stripe as the ―full stripe‖. But starting soon, HP Smart Array utilities, including ORCA and ACU, will be migrating to the use of the standard RAID terms of strip size and stripe size. This change will be incorporated over time as new releases of the utilities are required. So don't be surprised someday soon when you open the ACU to find that you are setting the strip size and not the stripe size. Additional resources Resource Home page for HP Smart Array controllers Storage Networking Industry Association online dictionary URL http://h18004.www1.hp.com/products/servers/proliantstorage/arra ycontrollers/index.html http://www.snia.org/education/dictionary/ 5