Re: Question regarding mmap on ZFS, or possibly Dovecot

On Sat, May 10, 2008 at 2:46 AM, Svein Skogen <svein-listmail_at_d80.iso100.no>
wrote:

> I still get massive file corruption when allowing Dovecot to run win mmap
> enabled on ZFS/FreeBSD RELENG_7 (as of one week ago), and I have seen
> symptoms of corruption with Samba and mmap on ZFS (although I cannot say
> with certainty that those samba files were corrupted in the FreeBSD end,
> they may have been mangled by my less-than-trustworthy windows).
>
> For dovecot+mmap+zfs I get a googlefull of results, same with
> samba+mmap+zfs.
>
> The question remains the same, however. Is this a problem with
> samba/dovecot using mmap incorrectly, a problem with ZFS as such, or a
> problem with the FreeBSD implementation of ZFS? I'm not asking this to have
> someone to point fingers at, but because I want to do some risk-reducing
> activities. If the problem is in the applications, disabling mmap in those
> applications will be a workaround. If the problem is with ZFS itself, or
> with FreeBSD, things start to get interesting (it would need some global
> switch to turn mmap off, and I'm not sure such a thing is
> practical/possible).
>
> The system running my ZFS is an Athlon64 running amd64 kernel, 4gb ram, and
> a raidZ of 3 500gb samsung disks (on an nForce430 chipset)


While I remain suspicious of ZFS on FreeBSD, I use it for /usr and /var on
my laptop and as a large filestore on my network (via both NFS and samba).

The only curious thing on my laptop is that wine crashes (even running
winecfg crashes) ... seemingly while mapping ntkrnl.dll (or whatever it's
called).  The big filestore seems reliable at holding media of various
sorts.  Both Samba and NFS are used to access it.

But I don't bit torrent directly to a ZFS filesystem and I don't use
dovecot.