Duncan <1i5t5.duncan <at> cox.net> writes: > > To those that know the details, this tells the story. > > Btrfs raid5/6 modes are not yet code-complete, and scrub is one of the > incomplete bits. btrfs scrub doesn't know how to deal with raid5/6 > properly just yet. > > While the operational bits of raid5/6 support are there, parity is > calculated and written, scrub, and recovery from a lost device, are not > yet code complete. Thus, it's effectively a slower, lower capacity raid0 > without scrub support at this point, except that when the code is > complete, you'll get an automatic "free" upgrade to full raid5 or raid6, > because the operational bits have been working since they were > introduced, just the recovery and scrub bits were bad, making it > effectively a raid0 in reliability terms, lose one and you've lost them > all. > > That's the big picture anyway. Marc Merlin recently did quite a bit of > raid5/6 testing and there's a page on the wiki now with what he found. > Additionally, I saw a scrub support for raid5/6 modes patch on the list > recently, but while it may be in integration, I believe it's too new to > have reached release yet. > > Wiki, for memory or bookmark: https://btrfs.wiki.kernel.org > > Direct user documentation link for bookmark (unwrap as necessary): > > https://btrfs.wiki.kernel.org/index.php/ > Main_Page#Guides_and_usage_information > > The raid5/6 page (which I didn't otherwise see conveniently linked, I dug > it out of the recent changes list since I knew it was there from on-list > discussion): > > https://btrfs.wiki.kernel.org/index.php/RAID56 > > <at> Marc or Hugo or someone with a wiki account: Can this be more visibly > linked from the user-docs contents, added to the user docs category list, > and probably linked from at least the multiple devices and (for now) the > gotchas pages? >
So raid5 is much more useless than I assumed. I read Marc's blog and figured that btrfs was ready enough. I' really in trouble now. I tried to get rid of raid5 by doing a convert balance to raid1. But of course this triggered the same issue. And now I have a dead system because the first thing btrfs does after mounting is continue the balance which will crash the system and send me into a vicious loop. - How can I stop btrfs from continuing balancing? - How can I salvage this situation and convert to raid1? Unfortunately I have little spare drives left. Not enough to contain 4.7TiB of data.. :( -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
