From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Fedyk Subject: Re: ReiserFS problems Date: Wed, 6 Aug 2003 15:08:17 -0700 Message-ID: <20030806220817.GG21290@matchmail.com> References: <20030806182055.A28562@bitwizard.nl> <3F31303A.6020408@namesys.com> <3F314BE8.50300@suse.com> <20030806212107.A3975@bitwizard.nl> <20030806213623.C3975@bitwizard.nl> Mime-Version: 1.0 Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: <20030806213623.C3975@bitwizard.nl> List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Rogier Wolff Cc: Jeff Mahoney , Hans Reiser , reiserfs-list@namesys.com, copy@harddisk-recovery.nl On Wed, Aug 06, 2003 at 09:36:23PM +0200, Rogier Wolff wrote: > P.S. We also sometimes do: > > while (1) > seek to random position (in randomly chosen 1G file) > write 1k > > we might benefit from a call that tells the filesystem: > Pretend that this file WILL grow to 1Gb, but leave it sparse for > now. > > So, the block to allocate if we seek to 500Mb past the beginning of the > file would be 500Mb further along the disk. That way the eventual image > will be linear. But leaving the intermediate blocks unallocated will > allow us to eventually use up that free space if we DO NOT end up > writing that area. Ahh, but sparse files are not handled effeciently at all with reiserfs. It is fixed properly in reiser4 though. There was a thread recently on this issue on the reiserfs list within the last week about this. If you use reiserfs, avoid large sparse files like the plague.