[Bug 1183699] Re: switch -D is not working

[Launchpad Bug Tracker]

Status changed to 'Confirmed' because the bug affects multiple users.

** Changed in: bonnie++ (Ubuntu)
       Status: New => Confirmed

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https://bugs.launchpad.net/bugs/1183699

Title:
  switch -D is not working

Status in “bonnie++” package in Ubuntu:
  Confirmed

Bug description:
  -D (O_DIRECT) is not working. (without -D everything runs fine)

  /usr/sbin/bonnie++ -n 1024 -D >> ~/squeeze-mpath-ext4d.csv
  Writing a byte at a time...Can't write() - disk full?

  echo $?
  1

  
  I think its an issue with O_DIRECT.

  man 2 open (notes section):
  --- snip ---
  O_DIRECT

  The O_DIRECT flag may impose alignment restrictions on the length and
  and address of userspace buffers and the file offset of I/Os.  Linux
  alignment restrictions vary by file system and kernel version and might
  be absent entirely.  However there is currently no file
  system-independent interface for an application to discover these
  restrictions for a given file or file system. [...]

  Under Linux 2.6, alignment to 512-byte boundaries suffices.
  --- snip ---

  I think its located at bon_io.cpp line 227 where you try to write 1
  byte:

      if(write(m_fd, &c, 1) != 1)
                     ^^  ^

  I think it is sufficient if both *buf and count are 512 byte.

  lsb_release -rd
  Description:    Ubuntu 13.04
  Release:        13.04

  apt-cache policy bonnie++
  bonnie++:
    Installed: 1.97.1
    Candidate: 1.97.1

  cheers
  -arsen

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