Date: Fri, 1 Jun 2001 00:03:18 -0500 From: Andrew Hesford <ajh3@usrlib.org> To: Kris Kennaway <kris@obsecurity.org> Cc: Andrew Hesford <ajh3@usrlib.org>, Rick Hamell <hamellr@heorot.1nova.com>, Christoph Kukulies <kuku@gilberto.physik.rwth-aachen.de>, questions@FreeBSD.ORG Subject: Re: 2GB filesize limit? Message-ID: <20010601000318.A47155@core.usrlib.org> In-Reply-To: <20010531214651.A14822@xor.obsecurity.org>; from kris@obsecurity.org on Thu, May 31, 2001 at 09:46:51PM -0700 References: <200105310943.f4V9hgX04825@gilberto.physik.rwth-aachen.de> <Pine.BSF.4.21.0105300906180.38491-100000@heorot.1nova.com> <20010531114130.A45461@core.usrlib.org> <20010531120721.F96927@xor.obsecurity.org> <20010531231841.B46862@core.usrlib.org> <20010531214651.A14822@xor.obsecurity.org>
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On Thu, May 31, 2001 at 09:46:51PM -0700, Kris Kennaway wrote: > On Thu, May 31, 2001 at 11:18:41PM -0500, Andrew Hesford wrote: > > On Thu, May 31, 2001 at 12:07:21PM -0700, Kris Kennaway wrote: > > > On Thu, May 31, 2001 at 11:41:30AM -0500, Andrew Hesford wrote: > > > > On Wed, May 30, 2001 at 09:06:54AM -0700, Rick Hamell wrote: > > > > > > What is currently FreeBSD's max file size? > > > > > > > > > > Maximum filesystem size is 2 gigablocks, maximum file size is 1 > > > > gigablock. > > > Actually the max FS size is 2^31 sectors (usually 512 bytes), not > > > blocks. That comes out to 1 TB. > > > > This is the maximum *partition* size. From /sys/ufs/ffs/fs.h, we have in > > the definition of "struct fs" the following: > > > > int32_t fs_size /* number of blocks in fs */ > > > > Hence a filesystem can have 2^31 blocks, or 2 gigablocks. > > > > For you, this means a whopping 32T filesystem (since you do use the 16k > > block size. > > How can you have a filesystem larger than a logical partition? AFAIK, > that limitation applies even if you're not using a single physical > partition (e.g. vinum/ccd). > > Kris I wish I could remember where exactly I saw it, but there are 4TB filesystems in existence today. A google.com/bsd search for something along the lines of "maximum filesystem freebsd" will turn up the right information. Of course, it just occurred to me that these could be 64-bit Alpha systems. Still, the filesystem limit doesn't have anything to do with the partition limit. You might not be able to *create* a 2 gigablock filesystem on a limited partition, but that doesn't mean the machine won't handle 32 bits of block addressing. Fixing the disklabel.h limitation (either by using a larger data structure than an integer, or by increasing the physical sector size on hard drives) would allow larger filesystems to be created without modifying filesystem code. You opt for the practical answer, saying a filesystem can't be bigger than the partition that contains it. I choose the theoretical one, saying that 2 gigablocks could be addressed with no trouble. -- Andrew Hesford ajh3@usrlib.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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