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 (8.13.1/8.13.1) with ESMTP id k9IHMDhW009118 for ; Wed, 18 Oct 2006 13:22:13 -0400 Received: from svc.anykey.de (service.anykey.de [213.168.80.18]) by mx3.redhat.com (8.13.1/8.13.1) with ESMTP id k9IHM88Q018687 for ; Wed, 18 Oct 2006 13:22:08 -0400 Received: from eu.main.anykey (unknown [192.168.200.17]) by svc.anykey.de (anykey GmbH) with ESMTP id 192835C6B5 for ; Wed, 18 Oct 2006 19:21:41 +0200 (CEST) Received: from [127.0.0.1] (service.anykey.de [213.168.80.18]) by eu.main.anykey (Postfix) with ESMTP id 0647C127E8 for ; Wed, 18 Oct 2006 19:21:57 +0200 (CEST) Message-ID: <453662B3.6000603@anykey.de> Date: Wed, 18 Oct 2006 19:21:55 +0200 From: Andreas Octav MIME-Version: 1.0 Subject: Re: [linux-lvm] "System ID" entry missing in metadata (LVM2) ?! References: <1591887.1161167319269.OPEN-XCHANGE.WebMail.wwwrun@eu.main.anykey> <3673884.1161175340523.OPEN-XCHANGE.WebMail.wwwrun@eu.main.anykey> <45365026.90006@anykey.de> In-Reply-To: Content-Transfer-Encoding: 8bit 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="utf-8"; format="flowed" To: LVM general discussion and development Sorry, i did not express myself correct: I do not want to share the logical volumes for the use of a Cluster Filesystem (OCFS etc.). I just want to be able to switch the volume groups from one host to another, so only one host at a time has access to a specific volume group. But if I do an vgimport on a host, every host that sees the VG can use it... I am going to install several Oracle/SAP instances in different Volume Groups and I want to be sure that only one host can access a specific VG at a time. The Veritas Volume Manager for example automatically sets a host id of the system that imports a VG (DiskGroup in Veritas terms) during an import, so any other system has to "force" an import, resulting in a loss of access on the former owner. Btw: In LVM1 the system ID is used: ..snip.. vgdisplay VG Name vg vgdisplay System ID PV_IMPKnoppix1077635774 vgdisplay Format lvm1 ..snap.. Is this obsolete in LVM2? Jonathan E Brassow schrieb: > I think it works in the reverse... > > vgexport adds a generic tag to the volume groups metadata, basically > saying "ignore me". Doing a 'vgs' on an exported volume group shows > the 'x' attribute; and trying to activate that volume group results in > "Volume group "" is exported". So, after performing this > operation, no-one can use the volume group (until vgimport is run). > > vgimport removes the generic tag, allowing the VG to be activated and > used again. One this command is run, anyone that can see the volume > group can use/alter the volume group. > > Think of it as "import/export from the set of usable volume groups". > > If you want to share the VGs, you have two options: > 1) Use clustered LVM2. This is really the best option. > 2) Set up your logical volumes on one machine (you should only use > linear or stripe in this scenario - never mirror or snapshot). Never > change the logical volume layout after creating it unless the other > hosts have deactivated the volume groups being shared. Run 'vgchange > -ay' on all machines that have access to the devices. > > Clustered LVM2 makes sure that all changes to a shared volume group > are serialized to prevent corruption and makes sure to > activate/deactivate volumes on a cluster-wide basis. If you are > never going to change anything (no risk of corruption or > inconsistencies), you might be able to get away with using LVM2 as it is. > > If you need more specialized access, you can use tags. > > Note, if you are sharing a logical volume, the application (or file > system) sharing that volume must be cluster-aware. > > brassow > > On Oct 18, 2006, at 11:02 AM, Andreas Octav wrote: > >> Hi, >> >> thanks for your response Jonathan, but I want to share the VGs >> between the hosts. So I hoped that there is something like this >> functionality: >> -> "vgimport VG" writes some kind of hostid (system_id?) in the metadata >> -> other hosts can�t access the VG >> -> "vgdeport VG" removes the ID, so anyone else can import the VG >> >> My C knowledge isn�t very good, but the sources seem to include a >> functionality like the one mentioned above. >> >> >> Kind regards, >> Andreas >> >> Jonathan E Brassow schrieb: >>> >>>>> Hi, >>>>> >>>>> i�m new to LVM2 and wondering if it�s possible to restrict access >>>>> to a >>>>> Volume Group to a single server (e.g. like under vxvm (vxdg >>>>> import/deport)). >>>>> If I import a VG by using vgimport it is still possible to access the >>>>> VG >>>>> on another node in a shared SAN environment. Can I prevent this >>>>> somehow? >>>>> >>>>> I�m using lvm2-2.01.14-3.6 on servers running SuSE SLES9 SP3 x86_64. >>>>> >>> >>> You can use tags to achieve this, or you can specify specific volume >>> groups and logical volumes in lvm.conf under "volume_list". >>> >>> brassow >>> >>> >>> _______________________________________________ >>> 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/ >>> >> >> _______________________________________________ >> 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/ >> > > > _______________________________________________ > 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/ >