Difference between revisions of "Talk:Btrfs"

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(Things to do: Cleaned up heading proposal. Added two new sections.)
(Things to do: Adding inline as no responses. Adding section for Btrfsck usage.)
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#### Move -> "'''GRUB'''"
 
#### Move -> "'''GRUB'''"
 
#### Move -> "'''Swap file'''"
 
#### Move -> "'''Swap file'''"
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#### New -> "'''Btrfsck'''"
 +
##### See -> https://bbs.archlinux.org/viewtopic.php?id=156100
 
### Move -> "'''See also'''"
 
### Move -> "'''See also'''"
  
[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 08:27, 28 November 2013 (UTC)
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Edits:
 
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[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 08:27, 28 November 2013 (UTC);
[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 04:03, 29 November 2013 (UTC)
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[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 04:03, 29 November 2013 (UTC);
 
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[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 04:10, 29 November 2013 (UTC);
[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 04:10, 29 November 2013 (UTC)
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[[User:AdamT|AdamT]] ([[User_talk:AdamT|Talk]]) 02:35, 4 December 2013 (UTC)
  
 
== Defrag on SSD ==
 
== Defrag on SSD ==

Revision as of 02:35, 4 December 2013

Comment about stability

Btrfs is still under heavy development; it might be useful if someone familiar with btrfs were to add a section commenting on its overall stability. Vikingurinn (talk) 16:52, 17 December 2012 (UTC)

Vikingurinn, I added a warning template to the introduction with links to the Btrfs Wiki regarding stability. They have a good discussion on the topic there. Personal statements to the stability of Btrfs is probably best polled on the BBS. -- AdamT (Talk) 08:50, 28 November 2013 (UTC)

RAID-1 or RAID-5?

"3 1TB disks in an md based raid1 yields a /dev/md0 with 1TB free space and the ability to safely loose 2 disks without losing data. 3 1TB disks in a btrfs volume with data=raid1 will allow the storage of approximately 1.5TB of data before reporting full. Only 1 disk can safely be lost without losing data."

That sounds more like some kind of weird, inefficient RAID-5 arrangement than RAID-1. I don't know btrfs enough to say it's wrong, but I know RAID-1 enough to question it?

Fukawi2 (talk) 23:52, 29 April 2013 (UTC)

See btrfs wiki:
btrfs combines all the drives into a storage pool first, and then duplicates the chunks as file data is created. RAID-1 is defined currently as "2 copies of all the data on different disks". This differs from MD-RAID and dmraid, in that those make exactly n copies for n disks. In a btrfs RAID-1 on 3 1TB drives we get 1.5TB of usable data. Because each block is only copied to 2 drives, writing a given block only requires exactly 2 drives spin up, reading requires only 1 drive to spinup.
-- Karol (talk) 15:59, 17 June 2013 (UTC)

btrfs with fsck hook and fstab pass

Apparently one does not need to have a btrfs partition fscked on boot, so there should be a '0' for 'pass' in the fstab for any btrfs partion. I had relatively slow boot ups with a pass of '1' (btrfs was root)

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/791020/comments/27

the genfstab script puts a '1' in for 'pass' by default

Genfstab should no longer set pass to 1. -- AdamT (Talk) 08:53, 28 November 2013 (UTC)

Things to do

Here are some items that seem to need addressing on this article. I am working on various parts of it at the moment.

  1. Reflow headings:
    1. Goals: Effective_Use_of_Headers#Use_of_headers_and_headings
      1. Helpful ideas:
        1. Effective_Use_of_Headers#False_multi-level_structure
          1. Side-note
          2. Auxiliary information
        2. Effective_Use_of_Headers#Multi-level_structure
          1. Group arguments
          2. Alternative arguments
          3. Contradictory arguments
        3. Effective_Use_of_Headers#The_header_text
        4. Article_Naming_Guidelines
          1. Specificity, "Descriptivity," Brevity, "Expandibility,"
      2. See Btrfs Wiki for ideas.
      3. See Beginners' Guide for ideas.
    2. Proposed changes
      1. "Installation" -> "Preparation"
        1. New -> "System Requirements"
        2. Remove -> "Additional packages"
          1. Move -> links to "See also" or "Related".
        3. "Partitioning" -> "Prepare the storage drive"
          1. OR: "Partitioning" (as a child) -> "Choose a partition scheme"
      2. New -> "Create file systems"
        1. "Creating a new file system" -> "New file systems"
          1. "Examples"
            1. New -> "Single-drive file systems"
            2. "Multi-device filesystem and RAID feature" -> "Multi-drive file systems"
              1. Reduce content, provide links to "Btrfs Wiki" instead.
        2. "Convert from Ext3/4" -> "Convert existing file system"
      3. New -> "Configuring the file system"
        1. OR: Move -> "Tips and tricks"
        2. Move -> "Mount options"
          1. "Copy-On-Write (CoW)" -> "Copy-on-write"
            1. "Checkpoint Interval" -> Merge
          2. Move -> "Compression"
        3. New -> "Skinny extents"
        4. Move -> "Sub-volumes"
        5. New -> "Quotas"
      4. New -> "File system management"
        1. Move -> "Balance"
        2. Move -> "Defragmentation"
        3. Move -> "Display used/free space"
        4. Move -> "Balance"
        5. Move -> "Snapshots"
      5. Move -> "Tips and tricks"
      6. New -> "Troubleshooting"
        1. Move -> "Encryption"
        2. Move -> "GRUB"
        3. Move -> "Swap file"
        4. New -> "Btrfsck"
          1. See -> https://bbs.archlinux.org/viewtopic.php?id=156100
      7. Move -> "See also"

Edits: AdamT (Talk) 08:27, 28 November 2013 (UTC); AdamT (Talk) 04:03, 29 November 2013 (UTC); AdamT (Talk) 04:10, 29 November 2013 (UTC); AdamT (Talk) 02:35, 4 December 2013 (UTC)

Defrag on SSD

The wiki currently recommends mount options for autodefrag see here; I thought defrag on SSDs was considered wasteful with no performance gains. Am I mistaken? Graysky (talk) 11:07, 28 November 2013 (UTC)

Hey Graysky, good point, but Btrfs seems to be a bit different in this regard (at least at present): Btrfs Wiki Gotchas, Btrfs Wiki Mount options, and Phoronix 3.11 Benchmarking.
Maybe after the bug mentioned in "Gotchas" is squashed it may not be necessary, but the developers mention adding autodefrag as a default in the future, and I am not clear whether or not this will be applied to both SSDs and HDDs. Further, noting the benchmarks from Phoronix, at worst autodefrag does not seem to have a performance hit on SSDs. If you have sources that indicate differently please let me know, but at present this is the best I have found. I will add a tentative note to the section in question in case others have similar questions. -- AdamT (Talk) 19:27, 28 November 2013 (UTC)