From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Helmut Hullen" Subject: Re: wrong values in "df" and "btrfs filesystem df" Date: 09 Apr 2011 20:15:00 +0200 Message-ID: References: <1302370000.23240.10.camel@nayuki> Reply-To: helmut@hullen.de Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <1302370000.23240.10.camel@nayuki> List-ID: Hallo, Calvin, Du meintest am 09.04.11: >> Nice picture. But it doesn't solve the problem that I need a >> reliable information about the free/available space. And I prefer >> asking with "df" for this information - "df" should work in the same >> way for all filesystems. > The problem is that the answer to the seemingly simple question: "How > much more data can I put onto this filesystem?" gets pretty hard with > btrfs. > Your case is one of the simpler ones - To calculate the remaining > space for files, you take the unused allocated data space (light blue > on my picture), add the unallocated space (white), divide by the raid > mode redundancy, and subtract some percentage (this is only an > estimate, of course...) of that unallocated space for the additional > metadata overhead. That's simple? Maybe I'm simple minded. But I expect the same meaning of the shown date with df regardless what kind of filesystem is mounted. But no test item for an IQ test. If the value of "available" is unresolvable then btrfs should not show any value. Ok - there's a problem slightly similar to the "available" value of compressed partitions. Viele Gruesse! Helmut