ealbrecht

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About ealbrecht

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  1. This post is from a 3Ware representative: "I looked into the benchmark results, and I found out why the 3ware Escalade card performed below expectations in the ATTO Bench32.exe benchmark results. When the Bench32.exe program runs in Direct I/O mode (i.e. the Direct I/O box is checked in the Bench32.exe program, which is the default), then all writes to the disk drive are sent with the FUA bit set (when Windows basic disks are used). FUA stands for Force Unit Access, and is defined for SCSI devices. The 3ware Escalade card, Adaptec 2400A, and the HighPoint RocketRAID card all appear as 'SCSI and RAID controllers' to Windows 2000. The FUA bit is a way that a computer program can ensure that data is written to the physical medium of the disk drive, and not just cache memory before it is acknowledged. Here is the definition from the SCSI spec, on page 15 of Information Technology - SCSI Block Commands - 2 (SBC-2), Revision 4 dated 28 July 2001: "Sometimes the application client may want to have the blocks of data read from the medium instead of from the cache memory. The force unit access (FUA) bit is used to indicate that the device server shall access the physical medium. For a write operation, setting FUA to one causes the device server to complete the data write to the physical medium before completing the command." When Bench32.exe is run on a Windows 2000 basic disk, with the Direct I/O box checked, all writes to the disk drive are done with the FUA bit set. The 3ware controller honors this bit, and sends a flush command to the disk drive after every write to ensure that the data is truly written to disk. That is why the 3ware card shows lower numbers. Even though the Adaptec 2400A and HighPoint RocketRAID cards receive the write command with the FUA bit set, they do not send the flush command to the disk drive. This can easily be verified using an ATA bus analyzer. When Bench32.exe is run on a Windows 2000 dynamic disk, then the FUA bit is not set when using Bench32.exe. As you can see from the benchmark results, this results in much better performance for the 3ware controller." David Graas 3ware Inside Sales Manager
  2. ealbrecht

    3Ware 7500-12 with WD1200JB combo

    If you want any kind of good write speeds make sure that your Win2k/XP hard drives are upgraded to dynamic disks.
  3. To fix this problem and get much higher write speeds you have to make your hard drives dynamic disks under Windows 2000 and Windows XP.