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Date:      Thu, 8 Jul 2010 12:46:44 +0200 (CEST)
From:      Oliver Fromme <olli@lurza.secnetix.de>
To:        cejkar@fit.vutbr.cz (Cejka Rudolf)
Cc:        Garrett Wollman <wollman@hergotha.csail.mit.edu>, hubs@freebsd.org
Subject:   Re: FreeBSD 8.1-RC2 Available...
Message-ID:  <201007081046.o68AkiUw083900@lurza.secnetix.de>
In-Reply-To: <20100708083522.GA89496@fit.vutbr.cz>

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Cejka Rudolf wrote:
 > I'm not ZFS expert either, but I have similar experiences and I rather
 > stayed with UFS2.

You can improve ZFS performance; there are some tuning guides
floating around.  But I think you will still not reach the
performance of a well-tuned UFS.  So it's propably better
indeed to stay with UFS if performance is the most important
aspect of the file system.

 > I think that long fsck is not such a big problem for
 > our mirrors and I can see on my 8 x 500 GB HW RAID-5 sequential reads
 > up to 300 MB/s using UFS2, instead of just 30 MB/s using ZFS (tested
 > both over RAID-5 and JBOD).

If fsck time is an issue, I recommend using gjournal and
put the journal on a separate fast disk, e.g. an SSD.
It won't affect read performance at all, and reduce write
performance only slightly, depending on access patterns.

 > The other problems are limited capabilities using IPv6 and I really
 > do not believe in identity of source and destination trees mirrored
 > using cvsup...

To be honest, I trust cvsup more than I trust rsync.  I've
had some horrible experiences with rsync and lost some
backups in the process; especially its error-handling seems
to be very bad.  For example, when the target file system
is full, all kinds of weird things happen, such as files
being moved to the wrong directory, plain files being
replaced by device nodes and similar oddities.

Well, maybe rsync was improved in the meantime; I didn't
dare to touch it in a while.  :-)

Just my 2 cents.

Best regards
   Oliver

-- 
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

FreeBSD-Dienstleistungen, -Produkte und mehr:  http://www.secnetix.de/bsd

"The most important decision in [programming] language design
concerns what is to be left out."  --  Niklaus Wirth



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