Results 1 to 3 of 3
  1. #1
    Join Date
    Mar 2007
    Posts
    167

    Unanswered: Should the "dsync" option be set to "dsync off" for raw devices?

    Dear All,

    Should the "dsync" option be set to "dsync off" for raw devices?

    I ran the sp_helpdevice system stored procedure and noticed the following...

    device_name physical_name description status cntrltype device_number low high
    -------------- ---------------------------------------------- --------------------------------------------------------- --------- ------------ ---------------- --------- ---------
    master /opt/sybase/data/d303-120m special, dsync on, default disk, physical disk, 120.00 MB 3 0 0 0 61439
    mxp_data01 /opt/sybase/data/d323-4g special, dsync off, physical disk, 4096.00 MB 2 0 5 83886080 85983231
    mxp_data02 /opt/sybase/data/d324-4g special, dsync off, physical disk, 4096.00 MB 2 0 6 100663296 102760447
    mxp_data03 /opt/sybase/data/d325-4g special, dsync off, physical disk, 4096.00 MB 2 0 7 117440512 119537663
    .................................................. .................................................. ................................................
    .................................................. .................................................. .......................
    .................................................. ..............................................
    mxp_log01 /opt/sybase/data/d315-2g special, dsync off, physical disk, 2048.00 MB 2 0 8 134217728 135266303
    mxp_log02 /opt/sybase/data/d302-100m special, dsync off, physical disk, 100.00 MB 2 0 19 318767104 318818303
    mxp_log03 /opt/sybase/data/d318-2g special, dsync off, physical disk, 2048.00 MB 2 0 15 251658240 252706815
    .................................................. .................................................. ................................................
    .................................................. .................................................. .......................
    .................................................. ..............................................
    sybmgmtdev /opt/sybase/data/d301-100m special, dsync off, physical disk, 100.00 MB 2 0 2 33554432 33605631
    sysprocsdev /opt/sybase/data/d305-200m special, dsync off, physical disk, 200.00 MB 2 0 1 16777216 16879615
    tapedump1 /dev/rmt4 disk, dump device 16 2 0 0 20000
    tapedump2 /dev/rst0 tape, 625 MB, dump device 16 3 0 0 20000
    tempdb_dev01 /opt/sybase/data/d313-2g special, dsync off, physical disk, 2048.00 MB 2 0 3 50331648 51380223
    tempdb_dev02 /opt/sybase/data/d314-2g special, dsync off, physical disk, 2048.00 MB 2 0 4 67108864 68157439

  2. #2
    Join Date
    May 2005
    Location
    South Africa
    Posts
    1,365
    Provided Answers: 1
    System Administration Guide
    Chapter 16 Initializing Database Devices
    Specifying the dsync setting with disk init
    The dsync setting is ignored for devices initialized on raw partitions, and for devices initialized on Windows NT files. In both cases, writes to the database device take place directly to the physical media.

  3. #3
    Join Date
    Mar 2007
    Posts
    167

    Million thanks... :)

    Thanks a million for sending the information you did. Makes sense. I was just puzzled because the default for master was "dysnc on" yet all other devices defaulted to "dysnc off". Then I remembered that the master database defaults to "dysnc on" to be on the safe side (just in case someone forgets to set it).

    Just as I read the information you sent, I remembered reading it before and forgot the information.

    Sincere thanks for your help.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •