There''s ad-hoc comment for various commands to recover from filesystem
errors.
But what do they actually do and when should what command be used?
(The wiki gives scant indication other than to ''blindly'' try
things...)
There''s:
mount "-o recovery,noatime"
btrfsck:
--repair try to repair the filesystem
--init-csum-tree create a new CRC tree
--init-extent-tree create a new extent tree
And there is "scrub"...
What do they do exactly and what are the indicators to try using them?
Or when should you ''give up'' on a filsystem and just retrieve
whatever
data can be read and start again?
All that lot sounds good for a wiki page ;-)
Thanks,
Martin
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Martin posted on Fri, 04 Oct 2013 16:47:19 +0100 as "condensed":> There''s ad-hoc comment for various commands to recover from filesystem > errors. > > But what do they actually do and when should what command be used? > What do they do exactly and what are the indicators to try using them? > Or when should you ''give up'' on a filsystem and just retrieve whatever > data can be read and start again? > > All that lot sounds good for a wiki page ;-)I recognize your name so you''re a regular poster and may well have seen this recover steps/order post from Hugo Mills, but you didn''t mention it, so... http://permalink.gmane.org/gmane.comp.file-systems.btrfs/27999 As you suggest, that should really go in the wiki (maybe it''s there already since that post, I haven''t actually checked recently, but your post reads as if you looked and couldn''t find a recovery list of this nature), but I''ve not gotten around to creating an account for myself there yet and committing it, and if no one else has either... But I do have it bookmarked for posting here, and for the day I do create myself that wiki account, if no one else has gotten to it by then... And while that answers what and what order, it doesn''t cover what the commands actually do or why you''d /use/ that order, and that''d be very good to add as well. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 04/10/13 19:32, Duncan wrote:> Martin posted on Fri, 04 Oct 2013 16:47:19 +0100 as "condensed": > >> There''s ad-hoc comment for various commands to recover from filesystem >> errors. >> >> But what do they actually do and when should what command be used? >> What do they do exactly and what are the indicators to try using them? >> Or when should you ''give up'' on a filsystem and just retrieve whatever >> data can be read and start again? >> >> All that lot sounds good for a wiki page ;-) > > I recognize your name so you''re a regular poster and may well have seenHail fellow Gentoo-er ;-) This is a prod from the thread: http://article.gmane.org/gmane.comp.file-systems.btrfs/28775> this recover steps/order post from Hugo Mills, but you didn''t mention it, > so... > > http://permalink.gmane.org/gmane.comp.file-systems.btrfs/27999 > > As you suggest, that should really go in the wiki (maybe it''s there > already since that post, I haven''t actually checked recently, but your > post reads as if you looked and couldn''t find a recovery list of this > nature), but I''ve not gotten around to creating an account for myself > there yet and committing it, and if no one else has either... > > But I do have it bookmarked for posting here, and for the day I do create > myself that wiki account, if no one else has gotten to it by then... > > And while that answers what and what order, it doesn''t cover what the > commands actually do or why you''d /use/ that order, and that''d be very > good to add as well.Yep. I''m using this as a bit of a test case as to how best to recover from whatever inevitable hiccups. All the more important to gain a good understanding before doing similar things to 16TB arrays... Comment/advice welcomed (please). Thanks, Martin -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html