From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordan Bobic Subject: =?UTF-8?Q?nilfs=5Fcleanerd=20using=20a=20lot=20of=20disk-write=20?= =?UTF-8?Q?bandwidth?= Date: Tue, 09 Aug 2011 11:18:12 +0100 Message-ID: <94b06fe504b540199f338f9bd4ed890f@mail.shatteredsilicon.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Hi, I'm seeing nilfs_cleanerd using a lot of disk write bandwidth according to iotop. It seems to be performing approximately equal amounts of reads and writes when it is running. Reads I can understand, but why is it writing so much in order to garbage collect? Should it not be just trying to mark blocks as free? The disk I/O r/w symmetry implies that it is trying to do something like defragment the file system. Is there a way to configure this behaviour in some way? The main use-case I have for nilfs is cheap flash media that suffers from terrible random-write performance, but on such media this many writes are going to cause media failure very quickly. What can be done about this? Gordan -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html