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Resize Raid 5

  • How could user resize RAID 5 properly without data loss? As a high performance, high data security and cost effective storage, RAID 5 still need resizing every now and then due to various needs. Now user should have recourse to third-party disk management software, such as MiniTool Partition Wizard to help resize RAID 5 partition.

    On RAID 5:
    A RAID 5 uses block-level striping with parity data distributed across all member disks. RAID 5 has achieved popularity because of its low cost of redundancy. This can be seen by comparing the number of drives needed to achieve a given capacity. As an example, four 1-TB drives can be made into a 2-TB redundant array under RAID 1 or RAID 1+0, but the same four drives can be used to build a 3-TB array under RAID 5. Although RAID 5 is commonly implemented in a disk controller, some with hardware support for parity calculations (hardware RAID cards) and some using the main system processor (motherboard based RAID controllers), it can also be done at the operating system level, e.g., using Windows Dynamic Disks or with mdadm in Linux. A minimum of three disks is required for a complete RAID 5 configuration. In some implementations a degraded RAID 5 disk set can be made (three disk set of which only two are online), while mdadm supports a fully-functional (non-degraded) RAID 5 setup with two disks which function as a slow RAID-1, but can be expanded with further volumes. In the example, a read request for block A1 would be serviced by disk 0. A simultaneous read request for block B1 would have to wait, but a read request for B2 could be serviced concurrently by disk 1.

    RAID 5 implementations suffer from poor performance when faced with a workload which includes many writes which are smaller than the capacity of a single stripe. This is because parity must be updated on each write, requiring read-modify-write sequences for both the data block and the parity block. More complex implementations may include a non-volatile write back cache to reduce the performance impact of incremental parity updates. Random write performance is poor, especially at high concurrency levels common in large multi-user databases. The read-modify-write cycle requirement of RAID 5's parity implementation penalizes random writes by as much as an order of magnitude compared to RAID 0. Performance problems can be so severe that some database experts have formed a group called BAARF - the Battle Against Any Raid Five. The read performance of RAID 5 is almost as good as RAID 0 for the same number of disks. Except for the parity blocks, the distribution of data over the drives follows the same pattern as RAID 0. The reason RAID 5 is slightly slower is that the disks must skip over the parity blocks.

    Resize RAID 5 with MiniTool Partition Wizard:
    To resize RAID5 with MiniTool Partition Wizard, user should first download it at MiniTool Partition Wizard Download Center. This disk management software is totally free for home and personal user to create partition, delete partition, format partition, wipe partition, merge partition, resize partition, copy partition, convert file system, etc.

    After running MiniTool Partition Wizard successfully, user would come to above interface, the main interface of MiniTool Partition Wizard. Here user should select desired RAID 5 partition and then click "Move/Resize" to enter next step.

    User could adjust partition size in this interface by dragging the left or right arrow.

    After settings, click "Apply" to execute pending operations.

    Lastly, click "OK" to finish operations.
    For more information on MiniTool Partition Wizard, please go to the official website https://www.partitionwizard.com/.