From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sander Subject: Re: SSD Optimizations Date: Thu, 11 Mar 2010 08:38:53 +0100 Message-ID: <20100311073853.GA26129@attic.humilis.net> References: <4B97F7CE.4030405@bobich.net> <93cdabd21003101512n6d773084hcf5e4a85aa180480@mail.gmail.com> <4B9829B1.1020706@bobich.net> Reply-To: sander@humilis.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-btrfs@vger.kernel.org To: Gordan Bobic Return-path: In-Reply-To: <4B9829B1.1020706@bobich.net> List-ID: Hello Gordan, Gordan Bobic wrote (ao): > Mike Fedyk wrote: > >On Wed, Mar 10, 2010 at 11:49 AM, Gordan Bobic wrote: > >>Are there options available comparable to ext2/ext3 to help reduce > >>wear and improve performance? With SSDs you don't have to worry about wear. > And while I appreciate hopeful remarks along the lines of "I think > you'll get more out of btrfs", I am really after specifics of what > the ssd mount option does, and what features comparable to the > optimizations that can be done with ext2/3/4 (e.g. the mentioned > stripe-width option) are available to get the best possible > alignment of data and metadata to increase both performance and life > expectancy of a SSD. Alignment is about the partition, not the fs, and thus taken care of with fdisk and the like. If you don't create a partition, the fs is aligned with the SSD. > Also, for drives that don't support TRIM, is there a way to make the > FS apply aggressive re-use of erased space (in order to help the > drive's internal wear-leveling)? TRIM has nothing to do with wear-leveling (although it helps reducing wear). TRIM lets the OS tell the disk which blocks are not in use anymore, and thus don't have to be copied during a rewrite of the blocks. Wear-leveling is the SSD making sure all blocks are more or less equally written to avoid continuous load on the same blocks. Sander -- Humilis IT Services and Solutions http://www.humilis.net