eeePC 900 with SSD && reducing writes

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Matthias Apitz

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Jun 24, 2008, 9:12:42 AM6/24/08
to freebsd...@freebsd.org

Hello,

I have installed FreeBSD 7.0R on that eeePC 900 and because of the
limited life time of the SSD (see
http://en.wikipedia.org/wiki/Wear_levelling )
I disabled some logging stuff which I don't need on that tiny laptop,
for example:

syslogd_enable="NO"
sendmail_enable="NONE"
cron_enable="NO"
newsyslog_enable="NO"

as well I have:

- not created any swap partition (the box runs fine with 1 GByte RAM)
- mount the file systems with 'noatime'
- put /tmp into memory file system with 128 MByte

any other ideas how to reduces unnecessary often-writes?

I'd also like to get rid of 'lastlog' and 'wtmp' but even if the man
page claims that they will not be created if they don't exist, they
come up again and again;

another candidate of not needed log is
/var/log/Xorg.n.log ...

thx

matthias
--
Matthias Apitz
Manager Technical Support - OCLC GmbH
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e <matthia...@oclc.org> - w http://www.oclc.org/ http://www.UnixArea.de/
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«...only once, which is enough if it has todo with definite truth.»
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Jeremy Chadwick

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Jun 24, 2008, 9:25:25 AM6/24/08
to Matthias Apitz, freebsd...@freebsd.org
On Tue, Jun 24, 2008 at 03:11:50PM +0200, Matthias Apitz wrote:
> Hello,
>
> I have installed FreeBSD 7.0R on that eeePC 900 and because of the
> limited life time of the SSD (see
> http://en.wikipedia.org/wiki/Wear_levelling )
> I disabled some logging stuff which I don't need on that tiny laptop,
> ...

> any other ideas how to reduces unnecessary often-writes?

Why bother? http://www.storagesearch.com/ssdmyths-endurance.html

--
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |

Rodrigo OSORIO (ros)

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Jun 24, 2008, 11:00:59 AM6/24/08
to freebsd...@freebsd.org


Hi,

Yes, you also can disable the file access time with the 'noatime' option in the fstab. See man mount(8).

Regards

Rodrigo OSORIO

Gary Jennejohn

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Jun 24, 2008, 11:16:14 AM6/24/08
to freebsd...@freebsd.org, Matthias Apitz
On Tue, 24 Jun 2008 06:24:12 -0700
Jeremy Chadwick <koi...@FreeBSD.org> wrote:

> On Tue, Jun 24, 2008 at 03:11:50PM +0200, Matthias Apitz wrote:
> > Hello,
> >
> > I have installed FreeBSD 7.0R on that eeePC 900 and because of the
> > limited life time of the SSD (see
> > http://en.wikipedia.org/wiki/Wear_levelling )
> > I disabled some logging stuff which I don't need on that tiny laptop,
> > ...
> > any other ideas how to reduces unnecessary often-writes?
>
> Why bother? http://www.storagesearch.com/ssdmyths-endurance.html
>

I've also seen test results in c't magazine where they did millions of
writes to the same physical sector and never saw any errors. The
manufacturers have really good internal wear leveling algorithms
which are totally transparent to the user.

---
Gary Jennejohn

Oliver Fromme

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Jul 8, 2008, 12:02:54 PM7/8/08
to freebsd...@freebsd.org, Matthias Apitz
Matthias Apitz wrote:
> I'd also like to get rid of 'lastlog' and 'wtmp' but even if the man
> page claims that they will not be created if they don't exist, they
> come up again and again;
>
> another candidate of not needed log is
> /var/log/Xorg.n.log ...

You can get rid of an on-disk /var alltogether.
Add these lines to /etc/rc.conf:

varmfs="yes"
varsize="32m"

It will create a memory FS for /var of 32 MB (default).

You could also mount some or all of your disk partitions
read-only. That's what I do on my embedded FreeBSD-driven
mp3 player (running from a CF card instead of hard disk),
because it doesn't have to write anything anywhere.

If you have any disk partitions that you mount read+write,
be sure to enable soft-updates because it tends to reduce
the number of physical write operations.

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

"FreeBSD is Yoda, Linux is Luke Skywalker"
-- Daniel C. Sobral

Matthias Apitz

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Jul 9, 2008, 6:17:23 AM7/9/08
to freebsd...@freebsd.org
El día Tuesday, July 08, 2008 a las 06:01:57PM +0200, Oliver Fromme escribió:

> Matthias Apitz wrote:
> > I'd also like to get rid of 'lastlog' and 'wtmp' but even if the man
> > page claims that they will not be created if they don't exist, they
> > come up again and again;
> >
> > another candidate of not needed log is
> > /var/log/Xorg.n.log ...
>
> You can get rid of an on-disk /var alltogether.
> Add these lines to /etc/rc.conf:
>
> varmfs="yes"
> varsize="32m"
>
> It will create a memory FS for /var of 32 MB (default).

Thanks for the hint, but memfs is not so good because you will loose
/var/db; I've created a symlink now from /var/log to /tmp/log and /tmp
is memfs;

> You could also mount some or all of your disk partitions
> read-only. That's what I do on my embedded FreeBSD-driven
> mp3 player (running from a CF card instead of hard disk),
> because it doesn't have to write anything anywhere.
>
> If you have any disk partitions that you mount read+write,
> be sure to enable soft-updates because it tends to reduce
> the number of physical write operations.

will think about tunefs and soft-updates; thx

matthias

--
Matthias Apitz
Manager Technical Support - OCLC GmbH
Gruenwalder Weg 28g - 82041 Oberhaching - Germany
t +49-89-61308 351 - f +49-89-61308 399 - m +49-170-4527211
e <matthia...@oclc.org> - w http://www.oclc.org/ http://www.UnixArea.de/
b http://gurucubano.blogspot.com/
«...una sola vez, que es cuanto basta si se trata de verdades definitivas.»
«...only once, which is enough if it has todo with definite truth.»
José Saramago, Historia del Cerca de Lisboa

Oliver Fromme

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Jul 9, 2008, 7:23:00 AM7/9/08
to freebsd...@freebsd.org, Matthias Apitz
Matthias Apitz wrote:

> Oliver Fromme wrote:
> > You can get rid of an on-disk /var alltogether.
> > Add these lines to /etc/rc.conf:
> >
> > varmfs="yes"
> > varsize="32m"
> >
> > It will create a memory FS for /var of 32 MB (default).
>
> Thanks for the hint, but memfs is not so good because you will loose
> /var/db; I've created a symlink now from /var/log to /tmp/log and /tmp
> is memfs;

It depends what you need from /var/db. In my case I didn't
need anything from it, so losing it was OK.

Another possibility is to create a "static" var directory
somewhere (on flash memory), e.g. /svar, and write a small
script or mtree file that creates symlinks from the memfs
/var to the static /svar, e.g. /var/db -> /svar/db.

Yet another solution would be to use unionfs, or a skeleton
tar.gz file that contains initial things for memfs /var.

There are many possibilities to choose from. :-)

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

"I started using PostgreSQL around a month ago, and the feeling is
similar to the switch from Linux to FreeBSD in '96 -- 'wow!'."
-- Oddbjorn Steffensen

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