Date: Mon, 03 Jun 2002 23:01:32 -0400 From: Bill Moran <wmoran@potentialtech.com> To: Drew Tomlinson <drew@mykitchentable.net> Cc: questions@freebsd.org Subject: Re: Drive Space - Am I Getting All I Should? Message-ID: <3CFC2D8C.5000906@potentialtech.com> References: <003101c20b3e$13a0d320$0301a8c0@bigdaddy>
next in thread | previous in thread | raw e-mail | index | archive | help
Drew Tomlinson wrote: > I added a 80G IDE drive to my 4.5 machine. I used /stand/sysinstall > to FDisk and Label the drive. Now after mounting, df -h shows: > > Filesystem Size Used Avail Capacity Mounted on > /dev/ad0s1e 72G 1.0K 66G 0% /ftp > > dmesg shows the drive as 76319M so 72G seems reasonable: > > ad0: 76319MB <GENERIC GENERIC> [155061/16/63] at ata0-master UDMA33 > > The /stand/sysinstall disklabel editor sees it as the same size: > > Part Mount Size Newfs Part Mount Size > Newfs > ---- ----- ---- ----- ---- ----- ---- - > ---- > ad0s1e /ftp 76319MB UFS Y > > But the FDISK partition editor sees the drive geometry differently > than dmesg: > > Disk name: ad0 FDISK Partition > Editor > DISK Geometry: 30629 cyls/81 heads/63 sectors = 156299787 sectors > > Offset Size End Name PType Desc Subtype > Flags > > 0 156301488 156301487 ad0s1 3 freebsd 165 > C> > > So how come df -h only shows 66G available? Where's the other 6G? Is > this some limitation of FBSD or my system BIOS? If this isn't in the FAQ, it should be. It's in certain man pages. The short answer is: Filesystem performance degrades very badly when a filesystem is more than 92% full, so the OS reserves 8% of the drive to keep performance reasonable. Only the root user can fill the disk more than 92% This is only a default value. You can change the reserved space on a drive with either tunefs or with options when you newfs it. I don't recommend it, though. The 8% thing was heavily researched and if you fill a drive fuller than that, saving data to it is going to take forever. -- Bill Moran Potential Technology http://www.potentialtech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3CFC2D8C.5000906>