Date: Sun, 06 Sep 2015 11:26:45 -0500 From: Brandon J. Wandersee <brandon.wandersee@gmail.com> To: Warren Block <wblock@wonkity.com> Cc: freebsd-questions@freebsd.org Subject: Re: Replacing Drive with SSD Message-ID: <8637yro6nu.fsf@WorkBox.Home> In-Reply-To: <alpine.BSF.2.20.1508281248500.74312@wonkity.com> References: <CEAD84AD-341A-4FB9-A3A1-D0D5A550AFFD@lafn.org> <55E01DAE.1020709@infracaninophile.co.uk> <20150828084643.GB1274@xtaz.uk> <864mjj1fh3.fsf@WorkBox.Home> <alpine.BSF.2.20.1508281248500.74312@wonkity.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Warren Block writes:
> The SSD keeps a map of which blocks have been written. So writing just
> once with dd is not a wear problem. The problem is that now the SSD has
> no way of knowing whether that block has real data on it or not. So it
> can't swap it for wear leveling. That's what trim does--when a file is
> deleted, the filesystem uses trim to notify the SSD that those blocks
> are no longer in use.
Would this also apply to a *single file* written using dd? Your SSD
guide recommends creating a swap file from /dev/zero using dd:
> Because the data goes through the file system, TRIM will be used, and
> the swap file can be resized without repartitioning the SSD.
So is the problem with dd and SSDs only relevant when targeting a whole
block device?
--
=================================================================
:: Brandon Wandersee ::
:: brandon.wandersee@gmail.com ::
==================================================================
'A common mistake that people make when trying to design something
completely foolproof is to underestimate the ingenuity of complete
fools.'
- Douglas Adams
==================================================================
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?8637yro6nu.fsf>