From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hubert Kario Subject: Re: [PATCH 2/2] Btrfs-progs: Add hot data support in mkfs Date: Wed, 1 Sep 2010 13:56:49 +0200 Message-ID: <201009011356.51609.hka@qbs.com.pl> References: <1281652177-23562-1-git-send-email-bchociej@gmail.com> <20100813131422.GA615@centrinvest.ru> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Cc: chris.mason@oracle.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cmm@us.ibm.com, bcchocie@us.ibm.com, mrlupfer@us.ibm.com, crscott@us.ibm.com, mlupfer@gmail.com, conscott@vt.edu To: Ben Chociej Return-path: In-Reply-To: List-ID: On Friday 13 August 2010 16:10:24 Ben Chociej wrote: > It's a good point, of course. Ideally we would be able to prioritize > data and place them on 15k versus 7.2krpm disks, etc. However you get > to a point where's there's only incremental benefit. For that reason, > the scope of this project was simply to take advantage of SSD and HDD > in hybrid. Of course, you could register the same complaint about the > ZFS SSD caching: why not take advantage of faster vs. slower spinning > disks? Unfortunately it just wasn't in the scope of our 12-week > project here. >=20 > That's not to say it *shouldn't* be done in the future, of course! > And, incidentally, you could hack it together at this point by settin= g > the /sys/block//queue/rotational flag to 0 and using it lik= e > an SSD. :) Then why not make the devices with rotational at 0 be the default "SSDs= " but=20 allow the admin to set manually others, without hacking? You can have SSDs in a hardware RAID array, this way the kernel may not= know=20 if the block device is on flash media or on rotational media... --=20 Hubert Kario QBS - Quality Business Software ul. Ksawer=F3w 30/85 02-656 Warszawa POLAND tel. +48 (22) 646-61-51, 646-74-24 fax +48 (22) 646-61-50 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753747Ab0IAL45 (ORCPT ); Wed, 1 Sep 2010 07:56:57 -0400 Received: from v002983.home.net.pl ([212.85.107.189]:51224 "HELO v002983.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752743Ab0IAL4z convert rfc822-to-8bit (ORCPT ); Wed, 1 Sep 2010 07:56:55 -0400 From: Hubert Kario Organization: QBS Jan =?utf-8?q?Kuba=C5=84?= To: Ben Chociej Subject: Re: [PATCH 2/2] Btrfs-progs: Add hot data support in mkfs Date: Wed, 1 Sep 2010 13:56:49 +0200 User-Agent: KMail/1.13.5 (Linux/2.6.35-ARCH; KDE/4.5.0; i686; ; ) Cc: chris.mason@oracle.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cmm@us.ibm.com, bcchocie@us.ibm.com, mrlupfer@us.ibm.com, crscott@us.ibm.com, mlupfer@gmail.com, conscott@vt.edu References: <1281652177-23562-1-git-send-email-bchociej@gmail.com> <20100813131422.GA615@centrinvest.ru> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Message-Id: <201009011356.51609.hka@qbs.com.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 13 August 2010 16:10:24 Ben Chociej wrote: > It's a good point, of course. Ideally we would be able to prioritize > data and place them on 15k versus 7.2krpm disks, etc. However you get > to a point where's there's only incremental benefit. For that reason, > the scope of this project was simply to take advantage of SSD and HDD > in hybrid. Of course, you could register the same complaint about the > ZFS SSD caching: why not take advantage of faster vs. slower spinning > disks? Unfortunately it just wasn't in the scope of our 12-week > project here. > > That's not to say it *shouldn't* be done in the future, of course! > And, incidentally, you could hack it together at this point by setting > the /sys/block//queue/rotational flag to 0 and using it like > an SSD. :) Then why not make the devices with rotational at 0 be the default "SSDs" but allow the admin to set manually others, without hacking? You can have SSDs in a hardware RAID array, this way the kernel may not know if the block device is on flash media or on rotational media... -- Hubert Kario QBS - Quality Business Software ul. Ksawerów 30/85 02-656 Warszawa POLAND tel. +48 (22) 646-61-51, 646-74-24 fax +48 (22) 646-61-50 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hubert Kario Subject: Re: [PATCH 2/2] Btrfs-progs: Add hot data support in mkfs Date: Wed, 1 Sep 2010 13:56:49 +0200 Message-ID: <201009011356.51609.hka@qbs.com.pl> References: <1281652177-23562-1-git-send-email-bchociej@gmail.com> <20100813131422.GA615@centrinvest.ru> Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: chris.mason@oracle.com, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cmm@us.ibm.com, bcchocie@us.ibm.com, mrlupfer@us.ibm.com, crscott@us.ibm.com, mlupfer@gmail.com, conscott@vt.edu To: Ben Chociej Return-path: Received: from v002983.home.net.pl ([212.85.107.189]:56077 "HELO v002983.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751870Ab0IAL4z convert rfc822-to-8bit (ORCPT ); Wed, 1 Sep 2010 07:56:55 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Friday 13 August 2010 16:10:24 Ben Chociej wrote: > It's a good point, of course. Ideally we would be able to prioritize > data and place them on 15k versus 7.2krpm disks, etc. However you get > to a point where's there's only incremental benefit. For that reason, > the scope of this project was simply to take advantage of SSD and HDD > in hybrid. Of course, you could register the same complaint about the > ZFS SSD caching: why not take advantage of faster vs. slower spinning > disks? Unfortunately it just wasn't in the scope of our 12-week > project here. >=20 > That's not to say it *shouldn't* be done in the future, of course! > And, incidentally, you could hack it together at this point by settin= g > the /sys/block//queue/rotational flag to 0 and using it lik= e > an SSD. :) Then why not make the devices with rotational at 0 be the default "SSDs= " but=20 allow the admin to set manually others, without hacking? You can have SSDs in a hardware RAID array, this way the kernel may not= know=20 if the block device is on flash media or on rotational media... --=20 Hubert Kario QBS - Quality Business Software ul. Ksawer=F3w 30/85 02-656 Warszawa POLAND tel. +48 (22) 646-61-51, 646-74-24 fax +48 (22) 646-61-50 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html