Subject: Re: what makes lost+found in NetBSD?
To: David Gilbert <dgilbert@pci.on.ca>
From: Matt Ragan <matt@ibmoto.com>
List: current-users
Date: 11/08/1995 17:59:47
David Gilbert wrote:
>
>>>>>> "After" == After 5 PM please slip brain through slot in door <greywolf@defender.VAS.viewlogic.com> writes:
>
>After> You are assuming that:
>
>After> - minfree is 10% - I meant "full, less minfree".
>
>After> In fact, I meant "full". As in "uid 0: write failed: No space
>After> left on device" full. As in "You have tromped all over
>After> minfree. Go directly to disk space hell. Do not asm("jmpa
>After> $_start"); do not collect even 200 bytes of disk space" full.
>
>After> As in "You forgot to make /usr big enough" full. As in "You
>After> have forgotten to delete the last five kernels from the root
>After> filesystem" full.
>
> From somewhere back in my conciousness, I seem to remember
>that inode space is separate from disk space that holds files in the
>filesystem --- and this is a major part of the design of the Berkeley
>File System. So... to be 'full' so that you couldn't create a file,
>the filesystem would have had to run out of inodes. I'm no expert,
>but isn't running out of inodes almost unheard of these days?
>
> When we were all using the last few bytes of disk space, we
>used to trim that parameter on newfs to the bone. I certainly don't
>do it anymore.
Actually, we run into not enough inodes on a regular basis, due to a
couple of different reasons:
a) We have some tools that create multi-gigabytes of really tiny files
in thousands of directories that completely tromp all over the
bytes/inode assumptions
b) a large (2+GB) filesystem checks much faster when the bytes/inode
count is dropped by using the '-i' parameter to newfs under the
4.2 filesystem (and possibly the 4.4 filesystem as well), that it
makes sense to raise the number of bytes/inode. Unfortunately,
this also makes it easier for some idiot suck up all of the inodes
by creating thousands of zero-length files
c) We have idiots who create thousands of zero-length files. It's almost
enough to want to slap them with inode quotas.
--
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Matt Ragan (matt@ibmoto.com) Motorola/IBM Somerset PowerPC Design Center
Network Administrator Systems/Network Engineering (512) 795-7298
9737 Great Hills Trail Austin, Tx 78759 FAX (512) 795-7519
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