Difference between revisions of "Talk:Btrfs"

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(RAID-1 or RAID-5?: see btrfs wiki)
m (Things to do: remove closed discussion)
 
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== Comment about stability ==
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{{Note|The name of the file system does not seem to have an official capitalization, so the rule for the ArchWiki has been arbitrarily set to use "Btrfs" (capital "B" and the rest lower-case); "btrfs" and "BTRFS" are therefore wrong spellings in this wiki. -- [[User:Kynikos|Kynikos]] ([[User talk:Kynikos|talk]]) 09:36, 6 January 2014 (UTC)}}
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. [[User:Vikingurinn|Vikingurinn]] ([[User talk:Vikingurinn|talk]]) 16:52, 17 December 2012 (UTC)
 
  
== RAID-1 or RAID-5? ==
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== "Displaying used/free space" needs rewrite ==
  
"''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'''.''"
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Section "Displaying used/free space" needs a rewrite. I will hopefully do that when I have time.
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* The example with /usr/bin/df is misleading (on simple setups it's reporting disk usage ('used' value) quite accurate).
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* "btrfs filesystem usage" should be mentioned on top
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* there should be a link to https://btrfs.wiki.kernel.org/index.php/FAQ#How_much_free_space_do_I_have.3F
  
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?
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{{unsigned|03:28, 17 November 2016‎|Mearon}}
  
[[User:Fukawi2|Fukawi2]] ([[User talk:Fukawi2|talk]]) 23:52, 29 April 2013 (UTC)
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== Proposal to add lzo compression warning ==
:See [https://btrfs.wiki.kernel.org/index.php/FAQ#What_are_the_differences_among_MD-RAID_.2F_device_mapper_.2F_btrfs_raid.3F btrfs wiki]:
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The [https://wiki.debian.org/Btrfs Debian btrfs page] has a warning about compress=lzo being possibly dangerous, citing the [https://www.spinics.net/lists/linux-btrfs/msg56563.html thread here]. I propose adding a warning section that simply notes this possibility and cites either the Debian wiki, the linked thread, or both. -- [[User:altercation|altercation]]
:''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.''
 
: -- [[User:Karol|Karol]] ([[User talk:Karol|talk]]) 15:59, 17 June 2013 (UTC)
 
  
== btrfs with fsck hook and fstab pass ==
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:It might be worth a note pointing to the thread, ''but'' the user in that thread [https://www.spinics.net/lists/linux-btrfs/msg58676.html reports he was using RAID6], which is already warned against in the wiki article. The rest of it seems to be just guessing that lzo is affecting it. Hard to know since he was using RAID6.  -- [[User:Rdeckard|Rdeckard]] ([[User_talk:Rdeckard|talk]]) 00:50, 23 March 2017 (UTC)
 
 
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
 

Latest revision as of 10:19, 11 April 2017

Note: The name of the file system does not seem to have an official capitalization, so the rule for the ArchWiki has been arbitrarily set to use "Btrfs" (capital "B" and the rest lower-case); "btrfs" and "BTRFS" are therefore wrong spellings in this wiki. -- Kynikos (talk) 09:36, 6 January 2014 (UTC)

"Displaying used/free space" needs rewrite

Section "Displaying used/free space" needs a rewrite. I will hopefully do that when I have time.

—This unsigned comment is by Mearon (talk) 03:28, 17 November 2016‎. Please sign your posts with ~~~~!

Proposal to add lzo compression warning

The Debian btrfs page has a warning about compress=lzo being possibly dangerous, citing the thread here. I propose adding a warning section that simply notes this possibility and cites either the Debian wiki, the linked thread, or both. -- altercation

It might be worth a note pointing to the thread, but the user in that thread reports he was using RAID6, which is already warned against in the wiki article. The rest of it seems to be just guessing that lzo is affecting it. Hard to know since he was using RAID6. -- Rdeckard (talk) 00:50, 23 March 2017 (UTC)