From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wes Felter Subject: Re: ssd optimised mode Date: Mon, 23 Feb 2009 16:19:25 -0600 Message-ID: References: <934e480c0902200326m7647d87cq28bfa1675ef012f4@mail.gmail.com> <20090220160134.GE24890@unused.rdu.redhat.com> <1235147425.13249.16.camel@think.oraclecorp.com> <3a7f57190902211707h37ff1478vdc0e5ffff66fa4da@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <3a7f57190902211707h37ff1478vdc0e5ffff66fa4da@mail.gmail.com> List-ID: Dmitri Nikulin wrote: > In the ideal future where SSDs can be run without a flimsy hardware > FTL I don't think this is likely at all for the same reasons Chris gave. > I've read that one of the potentially crippling limitations of ZFS is > that even its reliability features depend largely on being able to > perform atomic writes, which are currently impossible (?) on flash > media where a block has to be erased before it can be updated, clearly > not an atomic operation. Is there any solution to this that doesn't > depend on a battery backup? A COW write to a pre-erased block should be atomic. See TxFlash: http://storagemojo.com/2009/01/17/transflash/ Wes Felter - wesley@felter.org