From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lubos Kolouch Subject: Re: How to remount btrfs without compression? Date: Thu, 10 Nov 2011 06:57:07 +0000 (UTC) Message-ID: References: <4EB72C1B.1030702@parallels.com> <201111071319.14493.Martin@lichtvoll.de> <4EB87E01.1040704@parallels.com> <4EB880A0.1030304@gmail.com> <4EB88BC9.7020509@gmail.com> <4EB88D4A.5050908@parallels.com> <20111108150151.GA4954@shiny> <20111108151208.GB4954@shiny> <4EB9D0D9.1000009@parallels.com> <4EBA33DB.2070409@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: linux-btrfs@vger.kernel.org Return-path: List-ID: Dmitry Olenin, Wed, 09 Nov 2011 17:03:39 +0900: > On 11/09/2011 04:48 PM, Lubos Kolouch wrote: >> Sorry for possibly OT question - when I have historical btrfs system >> mounted with zlib compression, >> >> can I remount it with lzo ? What will happen? Will the COW be broken >> and the files taking duplicate space? Or will the Universe explode and >> be replaced with something even more bizzare? > > Hello Lubos If you have a kernel that supports lzo (don't quite remember > when it got in), why can't you? > Absolutely nothing will happen, and only the new/updated files will be > with lzo compression. You can remount on the fly switching b/w the two > compression options without any problems. Hello Dmitry, By the way, this is interesting question to me - I mounted the filesystem with -o compress=lzo, in dmesg showed btrfs: use lzo compression, but - the lzo module was not loaded (not shown in lsmod - and yes, I have it as a module). When I do modprobe lzo, it shows there. Isn't it a bit strange? So btrfs is using lzo module that was not loaded? (and says so in the dmesg output)? Thank you Lubos