[plug] Missing storage space

Jim Householder nofixed at westnet.com.au
Thu Mar 17 01:08:52 WST 2005

Matt Kemner wrote:
> Hi Jim
>>The numbers df gives me for it do not appear consistent.  I get
>>/dev/sda1  245409  2062  230676  1%  /media/removable
>>Now I expect the 245409 since manufacturers and computers use different
>>definitions of MB.  However I would expect total to equal used +
>>available.  What happened to the missing 12671 blocks?  Filesystem
>>overhead perhaps?
> You don't say which file system you are using, but most *nix type file
> systems reserve a small percentage of blocks for super-user access only
> (5% for ext2 and ext3) - once you hit that magical 95% limit the blocks
> available will be 0, but root will still be able to write to the disk
> until the used blocks matches the total.
> This is for historical reasons - it prevented a user from filling up the
> drive and causing catastrophic failures for daemons not written to handle
> low-disk-space situations - and in some cases even preventing the sysadmin
> from logging in to fix it.
> If you are using ext[23] then you can adjust the reserved blocks count
> with the -m [reserved-blocks-percentage] or -r [reserved-blocks-count] flags.
>  - Matt
Thanks.  I'm using ext2 and remember seeing something about space 
reserved for root when I created the filesystem.


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