From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Software RAID and TRIM Date: Thu, 30 Jun 2011 10:27:08 +1000 Message-ID: <20110630102708.6e443bd5@notabene.brown> References: <20110629204519.419474d2@notabene.brown> <87d3hwah9v.fsf@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <87d3hwah9v.fsf@gmail.com> Sender: linux-raid-owner@vger.kernel.org To: Namhyung Kim Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Wed, 29 Jun 2011 22:39:24 +0900 Namhyung Kim wr= ote: > NeilBrown writes: >=20 > > On Wed, 29 Jun 2011 11:32:55 +0100 (BST) Tom De Mulder > > wrote: > > > >> On Tue, 28 Jun 2011, Mathias Bur=E9n wrote: > >>=20 > >> > IIRC md can already pass TRIM down, but I think the filesystem n= eeds > >> > to know about the underlying architecture, or something, for TRI= M to > >> > work in RAID. > >>=20 > >> Yes, it's (usually/ideally) the filesystem's job to invoke the TRI= M=20 > >> command, and that's what ext4 can do. I have it working just fine = on=20 > >> single drives, but for reasons of service reliability would need t= o get=20 > >> RAID to work. > >>=20 > >> I tried (on an admittedly vanilla Ubuntu 2.6.38 kernel) the same o= n a two=20 > >> drive RAID1 md and it definitely didn't work (the blocks didn't ge= t marked=20 > >> as unused and zeroed). > >>=20 > >> > There's numerous discussions on this in the archives of > >> > this mailing list. > >>=20 > >> Given how fast things move in the world of SSDs at the moment, I w= anted to=20 > >> check if any progress was made since. :-) I don't seem to be able = to find=20 > >> any reference to this in recent kernel source commits (but I'm a c= omplete=20 > >> amateur when it comes to git). > > > > > > Trim support for md is a long way down my list of interesting proje= cts (and > > no-one else has volunteered). > > >=20 > Just out of curiosity, what are there in your list? :) >=20 >=20 http://neil.brown.name/blog/20110216044002 I have code for the first - the bad block log - and it seems to work. = But I really need to design and then perform some more testing. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html