Date: Sun, 04 Jun 2006 21:25:19 -0500 From: Eric Anderson <anderson@centtech.com> To: Duane Whitty <duane@dwlabs.ca> Cc: freebsd-fs@freebsd.org, Dave Stephens <hsoftdev17@gmail.com> Subject: Re: capacity issue? Message-ID: <4483960F.5000102@centtech.com> In-Reply-To: <20060604214841.GC960@dwpc.dwlabs.ca> References: <6845d25a0606041436j5f964aeeo7bc02b61b98b790a@mail.gmail.com> <20060604214841.GC960@dwpc.dwlabs.ca>
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Duane Whitty wrote: > On Sun, Jun 04, 2006 at 05:36:41PM -0400, Dave Stephens wrote: >> OS Version: FreeBSD 6.1 >> >> It seems like the capacity of my drive is being reported incorrectly >> by df. I'm not sure if this is a specific issue with the SATA drive >> or controller in the server, but I figured I would ask around. There >> is only 1 physical drive in this server. >> >> SATA Drive >> -------------------------------------------------------------------------------- >> ad8: 286168MB <Seagate ST3300822AS 3.AAD> at ata4-master SATA150 >> >> SATA Controllers >> -------------------------------------------------------------------------------- >> atapci1: <SiS 180 SATA150 controller> port >> 0xeff0-0xeff7,0xefe4-0xefe7,0xefa8-0xefaf,0xefe0-0xefe3,0xef >> 90-0xef9f irq 17 at device 5.0 on pci0 >> ata2: <ATA channel 0> on atapci1 >> ata3: <ATA channel 1> on atapci1 >> atapci2: <SiI 3112 SATA150 controller> port >> 0xefa0-0xefa7,0xef8c-0xef8f,0xef80-0xef87,0xef88-0xef8b,0xe >> f60-0xef6f mem 0xfebfac00-0xfebfadff irq 17 at device 9.0 on pci0 >> ata4: <ATA channel 0> on atapci2 >> ata5: <ATA channel 1> on atapci2 >> >> Note that atapci1 is built onto the motherboard and doesn't seem to be >> supported by FreeBSD at this time (no HDDs can be found during install >> when they are attached to it.) >> >> Mounting (dmesg) >> -------------------------------------------------------------------------------------------- >> swapon: adding /dev/ad8s2b as swap device >> Starting file system checks: >> /dev/ad8s1a: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s1a: clean, 221765 free (2981 frags, 27348 blocks, 1.2% >> fragmentation) >> /dev/ad8s4d: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s4d: clean, 9668716 free (980 frags, 1208467 blocks, 0.0% >> fragmentation) >> /dev/ad8s4f: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s4f: clean, 51380314 free (18 frags, 6422537 blocks, 0.0% >> fragmentation) >> /dev/ad8s3d: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s3d: clean, 28290946 free (32938 frags, 3532251 blocks, 0.1% >> fragmentation) >> /dev/ad8s3e: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s3e: clean, 9904253 free (1589 frags, 1237833 blocks, 0.0% >> fragmentation) >> /dev/ad8s4e: FILE SYSTEM CLEAN; SKIPPING CHECKS >> /dev/ad8s4e: clean, 37032718 free (998 frags, 4628965 blocks, 0.0% >> fragmentation) >> >> output from df >> --------------------------------------------------------------------------------- >> Filesystem Size Used Avail Capacity Mounted on >> /dev/ad8s1a 494M 61M 394M 13% / >> devfs 1.0K 1.0K 0B 100% /dev >> /dev/ad8s4d 19G 497M 17G 3% /home >> /dev/ad8s4f 98G 1.4G 89G 2% /photo >> /dev/ad8s3d 57G 2.8G 49G 5% /usr >> /dev/ad8s3e 19G 46M 17G 0% /var >> /dev/ad8s4e 76G 5.0G 65G 7% /www >> >> last time i checked (just as examples) >> 98G - 1.4G is not 89G (/photo) >> 57G - 2.8G is not 49G (/usr) >> 76G - 5.0G is not 65G (/www) >> >> Can anyone tell me what's going on here? >> >> Dave >> _______________________________________________ > > Hi, > > Avail = (Size - "elbow room") - Used > > The FFS algorithms need a little free space, about 5% I think, > in order to function efficiently. This is also why you can > df report a disk more than 100% used. > > Hth, > > Duane Whitty Right, it's 8% unless specified otherwise. Root is the only user that can use the reserved 8%, but usage of that space causes fragmentation and a performance penalty. Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------
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