Re: Problem converting data raid0 to raid1: enospc errors during balance

[Qu Wenruo <quwenruo@cn.fujitsu.com>]

-------- Original Message --------
Subject: Re: Problem converting data raid0 to raid1: enospc errors 
during balance
From: Chris Murphy <lists@colorremedies.com>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Date: 2014年10月27日 12:40
> On Oct 26, 2014, at 7:40 PM, Qu Wenruo <quwenruo@cn.fujitsu.com> wrote:
>
>> Hi,
>>
>> Although I'm not completely sure, but it seems that, you really ran out of space.
>>
>> [1] Your array won't hold raid1 for 1.97T data
>> Your array used up 1.97T raid0 data, it takes 1.97T for raid0.
>> But if converted to 1.97T, it will occupy 1.97T X2 = 3.94T.
>> Your array are only 2.73T, it is too small to contain the data.
> I'm not understanding. The btrfs fi show, shows 4x 2.73TiB devices, so that seems like it's a 10+TiB array.
>
> There's 2.04TiB raid0 data chunks, so roughly 500GiB per device, yet 1.94TiB is reported used per device by fi show. Confusing.
>
> Also it's still very confusing: Data, RAID1: total=2.85TiB, used=790.46GiB whether this means 2.85TiB out of 10TiB is allocated, or if it's twice that due to raid1. I can't ever remember this presentation detail, so again the secret decode ring where the UI doesn't expressly tell us what's going on is going to continue to be a source of confusion for users.
>
>
> Chris Murphy
Oh, I misread the output....

That turns strange now....
BTW what's the output of 'df' command?

Thanks,
Qu