On Sat, 01 Nov 2014 21:26:06 -0700 Robert White <rwh...@pobox.com> wrote:
> On 10/30/2014 07:09 PM, Chris Murphy wrote: > > Is hard to say. If a balance hasn't recently been done, the original device > > may have a good amount of free space in allocated chunks. I'm pretty sure > > Btrfs will write first to already allocated chunks with free space before > > allocating new chunks? So a bunch of stuff could actually still be on the > > original device - it just needs -o degraded,ro to get access to it. And if > > the current version of the file isn't retrievable because all or part of > > it's on the other drive, it'll just cause an error to occur. I think rsync > > and the like can be set to not fail on such errors, so anything that can be > > retrieved, is. > > Way back when he said that he "set the metadata to raid1" (or the > equivalent). That is, he didn't just rely on the default duplicaiton > onto the second drive. The only way I know to explicitly do that is with > the mfilter option to balance. So I'm pretty sure that, statistically, > about half his data is gone. But afaik balance with -mconvert=raid1 (and no other filters specified) shouldn't touch data at all, no? -- With respect, Roman -- 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
