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Date:      Tue, 29 May 2012 20:05:00 +0200
From:      Roland Smith <rsmith@xs4all.nl>
To:        Christer Solskogen <christer.solskogen@gmail.com>
Cc:        FreeBSD Mailing List <freebsd-questions@freebsd.org>
Subject:   Re: newfs on a SSD
Message-ID:  <20120529180500.GA92876@slackbox.erewhon.net>
In-Reply-To: <CAMVU60aNdCE26D41qOO99YoxHJFF1h8Mmd7=j1RmRmG-yv0mpA@mail.gmail.com>
References:  <CAMVU60aNdCE26D41qOO99YoxHJFF1h8Mmd7=j1RmRmG-yv0mpA@mail.gmail.com>

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On Fri, May 11, 2012 at 09:01:33AM +0200, Christer Solskogen wrote:
> After years of waiting for a decent price on one of these I finally
> got one. The questions is, which options should I use on a SSD that
> will be / on my system. I see that newfs supports TRIM, so that will
> be turned on, but should I use journaling? gjournal? softupdates? soft
> updates journaling? I'm confused :)

Enabling TRIM with the '-t' option for newfs sounds like a good idea. Assum=
ing
the underlaying device supports it. You can check that with the 'camcontrol
identify' command, assuming you're using the ada(4) driver.

OCZ has a page with tips for Linux. Some would apply to FreeBSD as well;
http://www.ocztechnologyforum.com/forum/showthread.php?54379-Linux-Tips-twe=
aks-and-alignment&highlight=3Dlinux

Aligning the partitions with the Erase Block Size is important. See:=20
https://wiki.archlinux.org/index.php/Solid_State_Drives

One thing to keep in mind is to mount the filesystems you make on the SSD w=
ith
the "noatime" option. This to avoid a lot of unnecessary writes.

Some of the newfs parameters like blocks per cilinder group don't seem to m=
ake
much sense for an SSD. Since the controller of the SSD already does all kin=
ds
of things to emulate a harddisk, I'm not sure if it makes much sense to tune
the filesystem's parameters much.

As for softupdates (journaled of not): try it and let us know if you see
differences, especially in write performance. :-)

The FreeBSD foundation has awarded a grant to port a special Flash filesyst=
em
and tools to FreeBSD:
http://freebsdfoundation.blogspot.com/2012/03/new-project-nand-flash-suppor=
t.html
It might be worthwhile to keep that in mind for the future.=20

What I would certainly recommend is that you make a daily automated backup
(may I suggest calling rsync from cron at night?) of the SSD's filesystem to
an actual HDD, just to be sure.

Roland
--=20
R.F.Smith                                   http://rsmith.home.xs4all.nl/
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