capacity issue?
Eric Anderson
anderson at centtech.com
Mon Jun 5 02:25:23 UTC 2006
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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