Overview of RAID Striping

Posted by Diwakar

Very simply, RAID striping is a means of improving the performance of large storage systems. For most normal PCs or laptops, files are stored in their entirety on a single disk drive, so a file must be read from start to finish and passed to the host system. With large storage arrays, disks are often organized into RAID groups that can enhance performance and protect data against disk failures. Striping is actually RAID-0; a technique that breaks up a file and interleaves its contents across all of the disks in the RAID group. This allows multiple disks to access the contents of a file simultaneously. Instead of a single disk reading a file from start to finish, striping allows one disk to read the next stripe while the previous disk is passing its stripe data to the host system -- this enhances the overall disk system performance, which is very beneficial for busy storage arrays.

Parity can be added to protect the striped data. Parity data is calculated for the stripes and placed on another disk drive. If one of the disks in the RAID group fails, the parity data can be used to rebuild the failed disk. However, multiple simultaneous disk failures may result in data loss because conventional parity only accommodates a single disk failure.

RAID striping
The performance impact of RAID striping at the array and operating system level.
RAID striping or concatenation: Which has better performance?
Designing storage for performance is a very esoteric effort by nature. There are quite a few variables that need to be taken into account.
RAID-50: RAID-5 with suspenders
RAID-50 combines striping with distributed parity for higher reliability and data transfer capabilities.
RAID-53: RAID by any other name
RAID-53 has a higher transaction rate than RAID-3, and offers all the protection of RAID-10, but there are disadvantages as well.
RAID-10 and RAID-01: Same or different?
The difference between RAID-10 and RAID-01 is explained.
RAID explained
RAID, or redundant array of independent disks, can make many smaller disks appear as one large disk to a server for better performance and higher availability.

1 Comments:

  1. kopparthi Says:
  2. Hi
    very informative post
    i'm new to SAN
    can you give any info about iSCSI ?

    appriciate u
    thanks

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