From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: Mass-Hardlinking Oops Date: Thu, 15 Oct 2009 20:27:07 +0200 Message-ID: <4AD7697B.8050406@wpkg.org> References: <4A74401B.90801@mccme.ru> <20090803145741.GC3765@think> <4A76FB78.5000207@wpkg.org> <20090803235920.C13173@mccme.ru> <87my3y3r8u.fsf@faran.nsc.liu.se> <3d0408630910111543t23bdf6c3u2274efc65f0fe06c@mail.gmail.com> <4AD2E3CF.6080701@wpkg.org> <20091012124726.GL2632@think> <87my3urf75.fsf@fftw.org> <20091015175541.GI30805@tracyreed.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Cc: Matteo Frigo , linux-btrfs@vger.kernel.org To: Tracy Reed Return-path: In-Reply-To: <20091015175541.GI30805@tracyreed.org> List-ID: Tracy Reed wrote: > On Tue, Oct 13, 2009 at 08:29:02PM -0400, Matteo Frigo spake thusly: >> Chris Mason writes: >> >>> Please keep in mind this is only a limit on the number of links to a >>> single file where the links and the file are all in the same directory. >> For the record, the nnmaildir mail backend in Gnus (an Emacs package >> for reading news and email) creates multiple hardlinks to the same >> file in the same directory. I had several thousands hardlinks at one >> time. > > I just found out that my company uses BackupPC for backups. It uses > hard links extensively: > > Features include: > > * A clever pooling scheme minimizes disk storage and disk > I/O. Identical files across multiple backups of the same or > different PC are stored only once (using hard links), resulting > in substantial savings in disk storage and disk writes. > > "clever" indeed. It creates filesystems with zillions of inodes which > are a pain to work with. What's hard to work with here? > This is the sort of large storage application > I would be looking to use btrfs for and apparently the currently > implementation would croak. Nope, they are created in separate directories, so no worries here. -- Tomasz Chmielewski http://wpkg.org