From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Trumpold Subject: Re: Does nilfs2 do any in-place writes? Date: Sat, 18 Jan 2014 08:25:07 -0800 Message-ID: References: Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-nilfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Clemens Eisserer , "linux-nilfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" On 1/18/14 1:44 AM, "Clemens Eisserer" wrote: >Hi again, > >> Rather, the issue on the flash devices may come from the current >> immature garbage collection algorithm. The current cleanerd only >> supports the timestamp-based GC policy which always tries to move the >> oldest segment first and even moves segments full of live blocks, >> thereby shortens the lifetime of flash devices. :-( > >It depends - for SSDs the timestamp policy is not optimal as it leads >to unnecessary writes. > >On the other hand, most cards only implement dynamic wear leveling >(wear leveling takes only place for areas that are written to, which >leads to very uneven wear distribution when there is mostly static >data) and also don't have read-disturb handling. >So for cards it is actually helpful to have the writes spread out >evenly and as a bonus there is no need to worry about read-disturb >effects =) > >Regards, Clemens >-- >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 Hi Clemens and group, Good information. So, is it true that the logging/cow nature of nilfs actually improves wear leveling by having 'writes spread out evenly'? Regards, Mark T. > -- 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