From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [172.16.45.118] (dhcp-118.brisbane.redhat.com [172.16.45.118]) by pobox.brisbane.redhat.com (8.13.1/8.13.1) with ESMTP id m115dseb010687 for ; Fri, 1 Feb 2008 15:39:55 +1000 Message-ID: <47A2B0C5.6010809@gmail.com> Date: Fri, 01 Feb 2008 15:40:21 +1000 From: David Robinson MIME-Version: 1.0 Subject: Re: [linux-lvm] LVM limits? References: <479DAD35.1080209@cesca.es> <479E2BEF.1090703@cesca.es> <1201541894.30560.24.camel@behemoth.csg.stercomm.com> <479E698C.10204@cesca.es> In-Reply-To: <479E698C.10204@cesca.es> Content-Transfer-Encoding: 7bit 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"; format="flowed" To: LVM general discussion and development Jordi Prats wrote: > Hi, > I'm the system administrator of PADICAT (http://www.padi.cat). It > collects Catalan (http://en.wikipedia.org/wiki/Catalonia) web sites to > provide permanent access to them (http://www.padi.cat/en/quees.php). > It's equivalent to Internet Archive (http://www.archive.org) but for a > particular culture. > > Our software developers require us to have one large file system, > actually a single directory, with all this historically-classified web > sites on a gziped file. > > I'm currently studying lustre and other HPC-related file systems to get > this large file system, but by now I have ext3 as our file system. Next > Monday I'm planning to extend it to 3TB o 4TB, so I'm currently > researching for restrictions because during next month I'll have between > 3TB to 4TB more to add: so, it will become a 8TB file system. > > Last time I fsck my 2'1TB file system I spend about 2 hours. Anyway, I'm > also curious about the maximums :P The man page for vgcreate talks a little bit about limits: "If the volume group metadata uses lvm1 format, extents can vary in size from 8KB to 16GB and there is a limit of 65534 extents in each logical volume. The default of 4 MB leads to a maximum logical volume size of around 256GB. If the volume group metadata uses lvm2 format those restrictions do not apply, but having a large number of extents will slow down the tools but have no impact on I/O performance to the logical volume." In short, you're more likely to reach filesystem limits before LVM's. EXT3 has a theoretical limit of 32 TB, but 32 GB its not practical. Creating an EXT3 filesystem larger than 8 TB is umm, brave - as you have noticed the tools (eg. fsck) do not scale well w/ EXT3. GFS or XFS (or others) may be more suitable, but it depends on your requirements. --Dave