Tuesday, July 24, 2012

FreeBSD Study #9

In last Frieday, FreeBSD Study #9 was held in KDDI Web Commnications' Office.


Today's session is "Managing storage on FreeBSD (vol.1)".
  • What haappens between physical devices and /dev/* file on FreeBSD
    • GEOM is the framework to give abstract tiers between these
  • GEOM class
  • GEOM provider
  • GEOM consumer
  • sysctl kern.geom.*
  • Sample for mirroring on GEOM
  • File system of UNIX
    • Provide approches to file content via the file name
    • Tree structure with a single root
  • Kernel does not necessarily need file systems
  • Userland needs file systems
  • UFS
    • default file system of FreeBSD
  • Structure of UFS
    • inode
    • super block
    • how to approch the block content with inode
  • fsck
    • Check where the inode is collapsed at
  • SoftUpdates
    • Improve performance of fsck
    • Do I/O in async with strict order to add/delete block
  • SoftUpdates + Jornal (SUJ)
    • Since FreeBSD 9.0, SoftUpdates support Journaling
    • Improve the performance more

In this day, Dr Hiroki Sato has explained about Filesystem, GEOM and UFS. I have understood what is UFS+SUJ. On next month, FreeBSD Study #10 will be held and this session will continue with the theme about ZFS.

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