Re: kern/38717: sysinst shouldn't create LFS file systems

[Alan Barrett <apb%cequrux.com@localhost>]

The following reply was made to PR kern/38717; it has been noted by GNATS.

From: Alan Barrett <apb%cequrux.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: netbsd-bugs%NetBSD.org@localhost
Subject: Re: kern/38717: sysinst shouldn't create LFS file systems
Date: Mon, 2 Jun 2008 00:24:27 +0100

 On Tue, 27 May 2008, Andrew Doran wrote:
 >  I have done a lot of stress testing on the file system code recently. Using
 >  a mixture of SGI fsstress, fsx, bonnie and postmark over different versions
 >  of NetBSD, my experience is that:
 >  
 >  - ffs, ext2fs, and tmpfs in -current /seem/ unbreakable
 >  - lfs and ffs+softdep can be broken within minutes
 >  - lfs in -current breaks within seconds
 
 For me, ffs used to be stable, but the past two or three months have
 been terrible.  Heavy file system activity such as rsync between two
 disks easily crashes the machine; I have never even managed to get a
 backtrace because the hotkey to flip to the console didn't work, so I
 haven't sent any PRs.  Twice recently I have noticed files that ended
 up with random binary content (of exactly the same size as the original
 file) after a crash.  (Both times, they were files that would have been
 created or overwritten shortly before the crash.)
 
 ffs with -o async is much worse than ffs without -o async; I suspect
 that it uses up all memory with buffers waiting to be written to disk,
 and then something fails due to lack of memory.  Again, I haven't been
 able to get backtraces.
 
 --apb (Alan Barrett)