From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id i8NHPNr01669 for ; Thu, 23 Sep 2004 13:25:23 -0400 Received: from mailhub.lss.emc.com (mailhub.lss.emc.com [168.159.2.31]) by mx1.redhat.com (8.12.11/8.12.10) with ESMTP id i8NHPHEd012095 for ; Thu, 23 Sep 2004 13:25:17 -0400 Received: from corpusic3.corp.emc.com (corpusic3.corp.emc.com [10.254.64.109]) by mailhub.lss.emc.com (Switch-3.1.6/Switch-3.1.6) with ESMTP id i8NHPDJa010069 for ; Thu, 23 Sep 2004 13:25:14 -0400 (EDT) Message-ID: <54E90801719C734E9969C98D40DE1E860836A89D@corpusmx2.corp.emc.com> From: lemons_terry@emc.com Date: Thu, 23 Sep 2004 13:25:12 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C4A192.489BEDBC" Subject: [linux-lvm] Extending a LVM2 strip set Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: To: linux-lvm@redhat.com Cc: Zhong_Jie@emc.com This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C4A192.489BEDBC Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi =20 http://www.tldp.org/HOWTO/LVM-HOWTO/mapmode.html states: =20 "In LVM 2, striped LVs can be extended by concatenating another set of devices onto the end of the first set. So you can get into a situation = where your LV is a 2 stripe set concatenated with a linear set concatenated = with a 4 stripe set. Are you confused yet?" =20 As a matter of fact, I am! =20 I need to start with a 2 disk (therefore, 2 stripe) logical volume, = that I later extend with 2 more disks. How is this done? =20 Thanks tl =20 Terry Lemons CLARiiON Applications Integration Engineering EMC=B2 =20 where information lives =20 4400 Computer Drive, MS D239 Westboro MA 01580 Phone: 508 898 7312 Email: Lemons_Terry@emc.com =20 =20 ------_=_NextPart_001_01C4A192.489BEDBC Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

http://www.tld= p.org/HOWTO/LVM-HOWTO/mapmode.html states:

"In LVM 2, striped = LVs can be extended by concatenating another set of devices onto the end of = the first set. So you can get into a situation where your LV is a 2 stripe = set concatenated with a linear set concatenated with a 4 stripe set. Are = you confused yet?"

As a matter of fact, I = am!

I need to start with a 2 disk = (therefore, 2 stripe) logical volume, that I later extend with 2 more disks. =A0How = is this done?

Thanks

Terry Lemons

CLARiiON Applications Integration Engineering

EMC=B2 &nbs= p;

= where information lives

4400 Computer Drive, MS = D239

Westboro MA = 01580

Phone: 508 898 = 7312

Email: Lemons_Terry@emc.com

------_=_NextPart_001_01C4A192.489BEDBC-- From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from null.msp.redhat.com (null.msp.redhat.com [172.16.31.120]) by pobox.corp.redhat.com (8.12.8/8.12.8) with ESMTP id i8NIjrck019297 for ; Thu, 23 Sep 2004 14:45:53 -0400 Sender: alewis@redhat.com Subject: Re: [linux-lvm] Extending a LVM2 strip set References: From: AJ Lewis Date: 23 Sep 2004 13:45:52 -0500 In-Reply-To: Message-ID: MIME-Version: 1.0 Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: LVM general discussion and development lemons_terry@emc.com writes: > http://www.tldp.org/HOWTO/LVM-HOWTO/mapmode.html > states: > > "In LVM 2, striped LVs can be extended by concatenating another set of > devices onto the end of the first set. So you can get into a situation where > your LV is a 2 stripe set concatenated with a linear set concatenated with a > 4 stripe set. Are you confused yet?" > > As a matter of fact, I am! > > I need to start with a 2 disk (therefore, 2 stripe) logical volume, that I > later extend with 2 more disks. How is this done? In lvm2 you simply create the lv with a stripe size of 2, then later when you want to extend it, you lvextend it with a stripe size of 2. The reason this is explained in so much detail is that in LVM1, you could not extend a striped set past its original PVs. In LVM2, the original striped set can be extended to the end of the original PVs, and any additional PVs become a striped set that is tacked on to the end (concatenated). Maybe an ACSII picture can help ;) Original striped volumes: ___ ___ | 1 | | 2 | | 3 | | 4 | |_5_| |_6_| After adding two more disks and lvextending: ___ ___ ___ ___ | 1 | | 2 | | 7 | | 8 | | 3 | | 4 | | 9 | | 10| |_5_| |_6_| |_11| |_12| So you have 2 sets of striped segments (with 2 stripes each), concatenated together. It does *not* remap all the striping so you have 1 set of striped segments (with 4 stripes each). Is that any clearer? -- AJ Lewis Voice: 612-638-0500 Red Hat Inc. E-Mail: alewis@redhat.com 720 Washington Ave. SE, Suite 200 Minneapolis, MN 55414 Current GPG fingerprint = D9F8 EDCE 4242 855F A03D 9B63 F50C 54A8 578C 8715 Grab the key at: http://people.redhat.com/alewis/gpg.html or one of the many keyservers out there... From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id i8O4O2r30947 for ; Fri, 24 Sep 2004 00:24:02 -0400 Received: from mailhub.lss.emc.com (mailhub.lss.emc.com [168.159.2.31]) by mx1.redhat.com (8.12.11/8.12.10) with ESMTP id i8O4O1eu024948 for ; Fri, 24 Sep 2004 00:24:01 -0400 Received: from corpusic1.corp.emc.com (corpusic1.corp.emc.com [168.159.129.100]) by mailhub.lss.emc.com (Switch-3.1.6/Switch-3.1.6) with ESMTP id i8O4NvfF019218 for ; Fri, 24 Sep 2004 00:23:58 -0400 (EDT) Message-ID: <54E90801719C734E9969C98D40DE1E860836A9F6@corpusmx2.corp.emc.com> From: lemons_terry@emc.com Subject: RE: [linux-lvm] Extending a LVM2 strip set Date: Fri, 24 Sep 2004 00:23:58 -0400 MIME-Version: 1.0 Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@redhat.com MUCH clearer. Thanks very much for the reply! If you have The Power, please consider adding this to the HOWTO document. Thanks again tl -----Original Message----- From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] On Behalf Of AJ Lewis Sent: Thursday, September 23, 2004 2:46 PM To: LVM general discussion and development Subject: Re: [linux-lvm] Extending a LVM2 strip set lemons_terry@emc.com writes: > http://www.tldp.org/HOWTO/LVM-HOWTO/mapmode.html > states: > > "In LVM 2, striped LVs can be extended by concatenating another set of > devices onto the end of the first set. So you can get into a situation where > your LV is a 2 stripe set concatenated with a linear set concatenated with a > 4 stripe set. Are you confused yet?" > > As a matter of fact, I am! > > I need to start with a 2 disk (therefore, 2 stripe) logical volume, that I > later extend with 2 more disks. How is this done? In lvm2 you simply create the lv with a stripe size of 2, then later when you want to extend it, you lvextend it with a stripe size of 2. The reason this is explained in so much detail is that in LVM1, you could not extend a striped set past its original PVs. In LVM2, the original striped set can be extended to the end of the original PVs, and any additional PVs become a striped set that is tacked on to the end (concatenated). Maybe an ACSII picture can help ;) Original striped volumes: ___ ___ | 1 | | 2 | | 3 | | 4 | |_5_| |_6_| After adding two more disks and lvextending: ___ ___ ___ ___ | 1 | | 2 | | 7 | | 8 | | 3 | | 4 | | 9 | | 10| |_5_| |_6_| |_11| |_12| So you have 2 sets of striped segments (with 2 stripes each), concatenated together. It does *not* remap all the striping so you have 1 set of striped segments (with 4 stripes each). Is that any clearer? -- AJ Lewis Voice: 612-638-0500 Red Hat Inc. E-Mail: alewis@redhat.com 720 Washington Ave. SE, Suite 200 Minneapolis, MN 55414 Current GPG fingerprint = D9F8 EDCE 4242 855F A03D 9B63 F50C 54A8 578C 8715 Grab the key at: http://people.redhat.com/alewis/gpg.html or one of the many keyservers out there... _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id i8OHB1r30924 for ; Fri, 24 Sep 2004 13:11:01 -0400 Received: from mailhub.lss.emc.com (mailhub.lss.emc.com [168.159.2.31]) by mx3.redhat.com (8.12.11/8.12.10) with ESMTP id i8OHAuCL023622 for ; Fri, 24 Sep 2004 13:10:56 -0400 Received: from corpusic3.corp.emc.com (corpusic3.corp.emc.com [10.254.64.109]) by mailhub.lss.emc.com (Switch-3.1.6/Switch-3.1.6) with ESMTP id i8OHAqRV018313 for ; Fri, 24 Sep 2004 13:10:53 -0400 (EDT) Message-ID: <54E90801719C734E9969C98D40DE1E860836AB36@corpusmx2.corp.emc.com> From: lemons_terry@emc.com Subject: RE: [linux-lvm] Extending a LVM2 strip set Date: Fri, 24 Sep 2004 13:10:44 -0400 MIME-Version: 1.0 Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-lvm@redhat.com So, when I add the two additional disks, which I want to be striped, I would do: lvextend --stripes 2 -- extents {nnnnn}{volumegroup} /dev/system/lvol0 And I'll end up with two 2-stripe sets, concatendated together? So, when data is written to these extending LV, will the data fill the first two striped disks before writing to the second two striped disks, or will writes be sent across all four disks? Thanks tl -----Original Message----- From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] On Behalf Of AJ Lewis Sent: Thursday, September 23, 2004 2:46 PM To: LVM general discussion and development Subject: Re: [linux-lvm] Extending a LVM2 strip set lemons_terry@emc.com writes: > http://www.tldp.org/HOWTO/LVM-HOWTO/mapmode.html > states: > > "In LVM 2, striped LVs can be extended by concatenating another set of > devices onto the end of the first set. So you can get into a situation where > your LV is a 2 stripe set concatenated with a linear set concatenated with a > 4 stripe set. Are you confused yet?" > > As a matter of fact, I am! > > I need to start with a 2 disk (therefore, 2 stripe) logical volume, that I > later extend with 2 more disks. How is this done? In lvm2 you simply create the lv with a stripe size of 2, then later when you want to extend it, you lvextend it with a stripe size of 2. The reason this is explained in so much detail is that in LVM1, you could not extend a striped set past its original PVs. In LVM2, the original striped set can be extended to the end of the original PVs, and any additional PVs become a striped set that is tacked on to the end (concatenated). Maybe an ACSII picture can help ;) Original striped volumes: ___ ___ | 1 | | 2 | | 3 | | 4 | |_5_| |_6_| After adding two more disks and lvextending: ___ ___ ___ ___ | 1 | | 2 | | 7 | | 8 | | 3 | | 4 | | 9 | | 10| |_5_| |_6_| |_11| |_12| So you have 2 sets of striped segments (with 2 stripes each), concatenated together. It does *not* remap all the striping so you have 1 set of striped segments (with 4 stripes each). Is that any clearer? -- AJ Lewis Voice: 612-638-0500 Red Hat Inc. E-Mail: alewis@redhat.com 720 Washington Ave. SE, Suite 200 Minneapolis, MN 55414 Current GPG fingerprint = D9F8 EDCE 4242 855F A03D 9B63 F50C 54A8 578C 8715 Grab the key at: http://people.redhat.com/alewis/gpg.html or one of the many keyservers out there... _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/