Maybe overkill for your application, but in case you haven't seen it:
http://www.embeddedarm.com/about/resource.php?item=466
I've implemented unionfs on a TS-7260 with the 2.6.21 kernel. I had to
play around with my partitions on the SD card and mod linuxrc-sdroot,
but I was able to get it to work. I can provide you with specifics, if
you decide to go that route.
Don
On 11/22/2013 5:09 PM, Joseph Bouchard wrote:
On 11/22/2013 12:41 PM, Clark Dunson wrote:
Hi everybody;
We use a TS-7260 with 2.6.21, SDBoot, read-only root, and read-write
/var. We have about 160 earthquake sites throughout the world and
remotely administer them from our central offices. We've been having
kernels remount /var as read-only more frequently these days, and are
looking for a better way to handle it, so ask the experts! Thank you.
I'm guessing you are getting corruption when someone unplugs the
power, then plugs in back in? I have had problems with that. What
about your setup has you mounting /var as read/write? Is that so the
O/S can write little pid files, etc, or are you writing your
earthquake data to /var? I have systems where the whole filesystem is
read only, then a tiny ram disk for /tmp/ and /var/tmp. That works
very well.
If you are writing data to it, I suggest keeping the card mounted R/O
most of the time, then when you have data to write go through a cycle of:
- fsck, -y /dev/whatever/is/your/var
- mount /var -o remount,rw
- write data
- sync
- mount /var -o remount,ro
That keeps your filesystem clean. In the rare case where you lose
power right in the middle of that write cycle (call that "one in a
thousand", the next fsck will hopefully clean it up. Then actual
corruption should be "one in a million".
Just my 2 cents worth.
Joe
smime.p7s
Description: S/MIME Cryptographic Signature
|