Re: LFS without lfs_cleanerd?

[Konrad Schroder <perseant%hitl.washington.edu@localhost>]

On Mon, 24 Mar 2008, J.T. Conklin wrote:

> What would be the expected failure mode of a LFS filesystem wasn't
> running the lfs_cleaner daemon?  Due to a packaging error, I had a
> wrong version of lfs_cleanerd in a NetBSD-based appliance firmware
> image. After some months, all writes to the filesystem blocked.

Yes, that would be the expected result if there is no lfs_cleanerd 
running.  The kernel automatically cleans empty segments, so you might not 
notice it for a while, but at some point you will likely need to clean to 
be able to write.

> operations) in a loop for about a week without being able to reproduce
> the failure. Is there any specific set of operations that would make a
> better accelerated wear test?

Try something like this.  Fill the filesystem to, say, 80% with small 
files, written sequentially (file0, file1, file2, ...; "small" means "much 
smaller than the segment size", maybe 1 block per file).  Then delete and 
rewrite the odd-numbered ones.  Most segments should be around half-full 
after the delete, so they won't be able to be reused without cleaning. 
Without segment reuse the filesystem would end up 120% full; it should 
block instead.

Take care,

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Konrad Schroder               Box 352195 -or- 14 Loew Hall, Stevens Way
Information Tech & Services                    University of Washington
Human Interface Technology Lab                  Seattle, WA, 98195, USA