From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Fajar A. Nugraha" Subject: Re: [PATCH] Btrfs: make lzo the default compression scheme Date: Fri, 27 May 2011 14:41:56 +0700 Message-ID: References: <4DDDCB57.6090405@cn.fujitsu.com> <20110527073212.GA28453@attic.humilis.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Li Zefan , "linux-btrfs@vger.kernel.org" To: sander@humilis.net Return-path: In-Reply-To: <20110527073212.GA28453@attic.humilis.net> List-ID: On Fri, May 27, 2011 at 2:32 PM, Sander wrote: > Li Zefan wrote (ao): >> As the lzo compression feature has been established for quite >> a while, we are now ready to replace zlib with lzo as the default >> compression scheme. > > Please be aware that grub2 currently can't load files from a btrfs with > lzo compression (on debian sid/experimental at least). > > Just found out the hard way after a kernel upgrade on a system with no > separate /boot partition :-) > > Found this: https://bugs.archlinux.org/task/23901 IIRC what matters is compression actually used by the files. If /boot/grub/* and kernel/initrd is not compressed, or compressed with zlib, then grub2 can read it just fine, even when the filesystem is usually mounted with -o compress=lzo (I'm using Ubuntu Natty). I think the move to use lzo compression by default is a good thing, since: - it's superior performance-wise to zlib - btrfs is not really recommended (yet) for production uses, so it's valid enough to assume users brave enough to use btrfs will know the necessary workarounds (like having separate /boot, or temporary remount with -o compress=zlib when upgrading kernel) - even if by accident you ended with unbootable system due to lzo, you can "fix" it using livecd and "btrfs filesystem defragment" to force the needed files to be uncompressed/compressed with zlib. -- Fajar