From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id 0A5AF7F58 for ; Thu, 28 Mar 2013 16:45:56 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay3.corp.sgi.com (Postfix) with ESMTP id 8782DAC002 for ; Thu, 28 Mar 2013 14:45:55 -0700 (PDT) Received: from pirx.askja.de (pirx.askja.de [83.137.103.148]) by cuda.sgi.com with ESMTP id iqcMc5dV82EHNG9y for ; Thu, 28 Mar 2013 14:45:54 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by pirx.askja.de (Postfix) with ESMTP id 6AA06300AD for ; Thu, 28 Mar 2013 22:45:51 +0100 (CET) Received: from pirx.askja.de ([127.0.0.1]) by localhost (pirx.askja.de [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 0j2W6j05ig6X for ; Thu, 28 Mar 2013 22:45:51 +0100 (CET) Date: Thu, 28 Mar 2013 22:45:50 +0100 From: Ralf Gross Subject: Re: Help with XFS in VMs on VMFS Message-ID: <20130328214550.GA3771@pirx.askja.de> References: <51549F09.1090109@hardwarefreak.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <51549F09.1090109@hardwarefreak.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com Stan Hoeppner schrieb: > On 3/28/2013 8:21 AM, Jan Perci wrote: > > > Normally I would use raw mappings and XFS directly on the volumes. But > > there is a hard requirement to support VM snapshots, so all the data must > > reside within VMDK files on the VMFS datastores. > > Since when? ESX has had LUN snapshot capability back to 3.0, 6 years or > so. It may have required the VCB add on back then. Snapshots are possible with RDM in virtual compatibily mode, not physical mode (> 2 TB). http://pubs.vmware.com/vsphere-51/topic/com.vmware.vsphere.storage.doc/GUID-0114693D-94BF-4D0E-9BA4-416D4A51A5A1.html > Is this simply a limitation of the freebie version? If so, pony up and > pay for what you need, or switch to a FOSS solution which has no such > limitations. No, thats the limit for all versions. > VMFS volumes are not intended for high performance IO. Unless things > have changed recently, VMware has always recommended housing only OS > images and the like in VMDKs, not user data. They've always recommended > using RDMs for everything else. IIRC VMDKs have a huge block (sector) > size, something like 1MB. That's going to make XFS alignment difficult, > if not impossible. I can't remember that I've every found this recommendation on a vmware page. http://blogs.vmware.com/vsphere/2013/01/vsphere-5-1-vmdk-versus-rdm.html > I cannot stress emphatically enough that you should not stitch 2TB VMDKs > together and use them in the manner you described. This is a recipe for > disaster. Find another solution. I'm seeing more and more requests for VMs with large disks lately in my env. Right now the max. is ~2 TB. I'm also thinking about where to go, > 2 TB ist only possible with pRDMs which can't be snapshotted. You have to use the snapshot features of your storage array. Ralf _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs