I don't know if this makes a lot of sense or any, but I was thinking that
flash memory doesn't like too many writes. So I was thinking of creating
one or two RAMdisks, for all those temporary reads and writes that I need,
and only store the final result on the flash.
The whole system will run from flash, true, but the directory with plenty
of writes and processing should run in RAM. So I'd like to create a drive
in RAM and then mount this drive as for the busy directory.

Does this make sense? If yes, how to do it?

Uwe

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You need memory file systems for that.

It is very easy under OpenBSD.

man mount_mfs

You have examples in Andreas Bihlmaier's liveCD writeup here.

http://openbsd-wiki.org/index.php?title=LiveCD

You typically have to create a tar zip of the mount file system and
untar it in the RAM disk and you are set.

It is a good idea to mount /tmp and /var on RAM disks.

-Girish

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Speaking of RAMdisks, have you checked out Gigabyte i-RAM? Might be
the right stuff for your need.

On Thu, Mar 27, 2008 at 11:36 AM, Girish Venkatachalam


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Not really. The legend of CF wearing out should also be worn out by now
for all practical purposes. When I first worked with the earliest nvram
the life was very short (in write cycles) now I cannot deliberately
wear out CF in any reasonable time.

Running an OpenBSD firewall on a Soekris using Apacer 256MB CF I used
the most verbose logging I could set up including for spamd handling 2
domains. After an install and two version installs (well over a year) I
moved spamd onto the mailserver it protects but I'm still using the
same old CF.

If you want to be really really conservative buy a good brand, much
larger than you need (= more spare cells) and replace it annually. Send
your cast offs to any developer who would like to have them and he will
get years of service out of most of them.

Fiddle-arsing around doing fancy installs and using up limited RAM to
be pretend disks ain't worth the effort. Generic installs Just Work
(TM) and I've never lost a CF on client machines either and some of
those are really busy little firewalls handling roadwarrior VPNs for a
financial services company of considerable repute.

The CF wearout meme needs to die.

On-list replies will suffice. Private replies only to the reply-to:

Rod/
/earth: write failed, file system is full
cp: /earth/creatures: No space left on device

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Specs, it's all about specs, it seems a fact to me that "standard" CF 
cards, as used in camera's, often without any technical specification 
other than "size", cannot be written as often as ordinary harddisks.

The foreseeable future people need to be really careful while choosing 
memory cards as hard disk replacements.

+++chefren

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The Apacer cards I use are PhotoSteno III made for camera use and I
cannot kill one.
Maybe you can wear one out in several years but you will never have a
head crash or motor failure. SanDisk gives a five year warranty with no
mention of write cycle limitations and I did see a data sheet somewhere
that showed you could shoot a CF full of pix every day and erase them
every night for 27 years and still not reach the write cycle limit. I
cannot remember what brand that was.

I have lost cout of failed HDDs around here and never lost a byte on
CF. There are nearly as many CFs here as HDDs now and if you have a
look at new laptops you'll see more and more SSHD and hybrids every
time a new model comes out.

Practically speaking if you buy a decent brand of CF or spend the extra
on an "industrial" model you can expect years of service out of it. I'm
sure that Bamboo Charlie makes cheapies in CF as well as mobos and

Bought any Seagate drives lately?

Rod/
/earth: write failed, file system is full
cp: /earth/creatures: No space left on device

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I have my old IBM ValuePoint 486 that has a bios that really only likes
drives under 512 MB.  It has worked with one 8 GB drive, but not another
seemingly identical WD 8 GB drive, yet alone a new-off-the-shelf 80 GB
PATA drive.  The IBM bios has no adjustability (as does the Award bios),
but instead just displays the size of the hard drive found.  If it
displays a size, it will boot from it, if not, it declares a hardware
error and won't boot from anything.

I wonder if a 512 MB CF card in a PATA-CF adapter would be a solution in
this case.  The box would likely do remote-logging anyway.

Does a CF card in a PATA-CF adapter look just like a HD, bootable and
all, to old BIOS?

Doug.

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The one I use does.
Rod/
/earth: write failed, file system is full
cp: /earth/creatures: No space left on device

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maybe, maybe not.
Rod's right, though...  I've never seen a flash media die from "write
fatigue".

I have seen and heard of a fair number die for other reasons.

There are reasons to use flash media.  Reliability is not one of them
in my mind.  They are small, they are quiet, they are low power, they
are vibration resistant.  They last a long time...usually.  But they

I agree, but not for the reasons usually given.

If you are using a flash drive to avoid worrying about failures, you
are fooling yourself..even if the flash drives were PERFECT, there are
other parts of the computer that fail, and there are user errors.  SO,
you still need the EXACT SAME recovery processes in place for flash
drives as you do for disks.  Using flash doesn't let you dodge recovery
and backup needs.

If you try to shoe-horn a big system into a small flash drive and make
something you don't properly maintain (key issue is DO YOU maintain it,
not COULD you maintain it.  Doesn't matter what you could do if you
don't), the system will be less reliable.

If you have an app where you need or want low power, quiet or small,
go ahead, use flash media, but for goodness sake, don't screw up a
really good OS by trying to meet some goal that is completely bogus.
Just use it as normal, and maintain it as normal.  Odds are, something
else will take your system down long before write fatigue does, most
likely, it will be your butchery of a working solution.

It's the unexpected downtime that counts, not the reason.  Who the
frick cares that you tried to avoid a one-in-five-year hypothetical
failure if you caused several days of very non-hypothetical downtime
as a result?  A simple, standard install will out-perform your
hacked up mess every time.

Someone posted an article recently about people liking to use Linux
because they like tweaking and adjusting and working with the system.
I've worked with people like that -- they are smart and clever and
will cause hours of downtime to avoid a totally ...
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