21. juli 2001 - 00:35Der er
15 kommentarer og 2 løsninger
Software Raid i Win2k
Jeg har tænkt på at prøve at lave software raid i Win2k. Jeg har 2 IBM 60GXP 40 GB, og har hørt at man kan gøre det. Hvis jeg nu gør det, og skal til at slette min Windows. Ville Raid\'en så også blive slettet? Og hvordan gør man det?
RAID er noget du skal opstille fysisk ved hjælp af en onboard RAID controller (hvis dit motherboard har sådan et) eller på en RAID controller (på en af PCI portene).
Det er nu ikke løgn at man kan lave Software Raid i Win2k. Jeg har optil flere venner som har hørt om det. Men spørgsmålet er om dataerne bliver hvis man sletter sit OS
Choosing between mirrored and RAID-5 volumes depends on your computing environment. RAID-5 volumes are a good solution for data redundancy when most activity consists of reading data. For example, if your network has a server on which you maintain all copies of the programs used by the people at that site, this might be a good case for using a RAID-5 volume. It enables you to protect the programs against the loss of a single disk in the striped volume. In addition, the read performance improves because of the concurrency of the reads across the disks that make up the RAID-5 volume.
In an environment in which frequent updates to the information occur, using mirrored volumes is usually better. However, you can use a RAID-5 volume if you want redundancy and if the storage overhead cost of a mirror is prohibitive.
Mirrored volumes: Support FAT and NTFS Can mirror system or boot volumes Require 2 hard disks Have higher cost per megabyte (50 percent utilization) Have good read and write performance. Use less system memory Support only 2 hard disks A mirrored volume is a fault-tolerant volume that duplicates your data on two physical disks. It provides data redundancy by using a copy (mirror) of the volume to duplicate the information contained in the volume. The mirror is located on a different disk. If one of the physical disks fails, the data on the failed disk becomes unavailable, but the system continues to operate using the unaffected disk. A mirrored volume is slower than a RAID-5 volume in read operations but faster in write operations.
In Windows NT 4.0 and earlier, a mirrored volume was known as a mirror set.
Mirrored volumes protect a volume on a disk from media and, possibly, controller failure by maintaining a fully redundant copy on another disk. When a mirrored volume fails, you must break the mirrored volume to expose the remaining volume as a separate volume with its own drive letter. You can then create a new mirrored volume with unused free space of the same size or greater on another disk.
To create a mirrored volume, you create a volume using free space on another disk. If the second volume is larger, the remaining space becomes free space. The same drive letter is used for both volumes. Any existing volume, even the system and boot volumes, can be mirrored onto another volume of the same size or greater on another disk using either the same or a different controller. When creating mirrored volumes, it is best to use disks that are the same size, model, and manufacturer.
Mirrored volumes have better overall read and write performance than RAID-5 volumes. Another advantage of mirrored volumes over RAID-5 volumes is that there is no loss in performance when a member of a mirrored volume fails. Mirrored volumes are more expensive in terms of dollars per megabyte because disk space utilization is less. However, the entry cost of a mirrored volume is lower because it requires only two disks, whereas RAID-5 volumes require three or more disks.
Mirrored volumes reduce the chance of an unrecoverable error by providing a duplicate set of data, which doubles the number of disks required and the input/output (I/O) operations when writing to the disk. However, some performance gains are achieved for reading data because of I/O load balancing of requests between the two volumes.
When you want to use the space in a mirrored volume for other purposes, you must first break the mirrored volume relationship and then delete one of the volumes. Breaking the mirrored volume does not delete the information, but it is still safer to do a backup first.
In the case of an unrecoverable error on a volume within a mirrored volume, you need to break the mirrored volume relationship to expose the remaining volume as an individual volume. You can then reassign some free space on another disk to create a new mirrored volume.
RAID-5 volumes: Support FAT and NTFS Cannot stripe system or boot volumes Require a minimum of 3 hard disks Have lower cost per megabyte Have moderate write performance and excellent read performance Require more system memory Support up to 32 hard disks Using RAID-5 volumes A RAID-5 volume is a fault-tolerant volume with data and parity striped intermittently across three or more physical disks. If a portion of a physical disk fails, you can re-create the data that was on the failed portion from the remaining data and parity. RAID-5 volumes are a good solution for data redundancy in a computer environment in which most activity consists of reading data.
In Windows NT 4.0 and earlier, a RAID-5 volume was known as a striped set with parity.
Disk Management offers limited support of RAID-5 volumes on basic disks. You can repair, regenerate the parity of, and delete RAID-5 volumes, but you cannot create new RAID-5 volumes on basic disks. You can create RAID-5 volumes only on dynamic disks.
RAID-5 volumes have better read performance than mirrored volumes. However, when a member is missing, such as when a disk has failed, the read performance is degraded by the need to recover the data with the parity information.
Nevertheless, this strategy is recommended over mirrored volumes for programs that require redundancy and are primarily read-oriented. Write performance is reduced by the parity calculation. Also, a write operation requires three times more memory than a read operation during normal operation. Moreover, when a volume fails, reading requires at least three times more memory than before the failure. Both conditions are caused by the parity calculation.
RAID-5 volumes include one parity block per stripe. Therefore, you must use at least three, rather than two, disks to allow for the parity information. Parity stripes, as shown in the following illustration, are distributed across all the volumes to balance the I/O load.
RAID-5 provides data redundancy at a cost of only one additional disk for the volume. However, recovery from the failure of a disk in a RAID-5 volume is more time-consuming than for a mirrored volume.
When you want to recover the space in a RAID-5 volume for other purposes, be sure to back up the information in it first, if you want to reuse that information. Then delete the volume.
Det du der har fundet, er en slags spejl af en eller flere harddiske. En slags backup. Hvis man bruger RAID 0 skriver man fx. 16 kb på den ene HD og 16 på den næste. På den måde skriver og læser man hurtigere. 2 40gb hd\'s bliver således til en 80 GB partition ikke 1 40 gb, som så bliver spejlet for sikkerhed.
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