--- In Samuel M Smith <> wrote:
>
>
> I have had problems with file system corruption on a 7400 rooting from
> the SD Card.
> Although there was some useful information in a prior thread, ( SD
> card corruption 09 March 2008)
> it didn't address my problem specifically. I would appreciate some
> suggestions on how to reliably use the SD Card given
> inadvertent power cycles.
>
> My configration is a 7400 using debian sarge 2.4 kernel, standard
> Technologic SD image distribution.
> uses the linuxrc-sdroot script to root from the sd card and mounted
> fstab
> /dev/sdcard0/disc0/part3 / ext2
> defaults,noatime,async 1 1
>
>
> The specific problem is that whenever the 7400 is powered off without
> running shutdown, on the next bootup
> fsck shows errors. Usually fsck is able to fix all the errors.
>
> The problem occurs when the unit is not allowed to complete fsck
> before being powered off again. That is if it
> gets powered off during fsck of the root on SD card then it could be
> non-recoverable.
>
> Since the 7400 is part of a larger system, I have no control over when
> or how fast the larger system is
> powered on or off. During testing or setup of other parts of the
> system, the 7400 might get repeated power cycles within a few seconds
> of each other
> which is not enough time for fsck to complete.
>
> In prototype testing, I have twice had the SD card get unrecoverably
> corrupted, ( fsck can't fix it automatically) so the 7400 does not boot.
> I have had to re flash the sd card. These are new sd cards.
>
> It seems to me that I need to disable the automatic fsck on bootup.
> But if I do that, I am concerned about the long
> term reliability of the file system on the sd card?
>
> In the previous post, teadapt was using the ext3 journaling file
> system. Apparently I can convert an ext2 to ext3 easily using fstune
> but I don't think ext3 is supported in the standard TS kernel for the
> 7400.
> Is JFS?
>
> I am new to using Linux in an embedded system. I have used VXWorks and
> NetOS where the OS is in NOR flash and doesn't get corrupted
> by inadvertent power cycles.
>
> The selection of the 7400 was based on having the resources provided
> by a full debian distribution (not TSLinxu). So if
> I can't reliably boot from SD Card given inadvertent power cycles,
> then its not a viable platform for me.
>
> What sort of corruption will creep in if I don't fun fsck every time
> it boots?
> What is the best practice for managing fs corruption with embedded
> linux given inadvertent power cycles?
>
> My application only needs to write to disk for logging. Right now I
> have a single 1GB SD card with OS and application files on the same
> partition, but
> I could put my application log files on a separate partition. But
> there are still some system logs that I would like to have (at least
> during testing).
>
> I want my application logs to survive a power cycle so using a ramfs
> as someone suggested won't work but my log rate is slow and disk
> performance
> is not an issue so I don't think the extra load of using a journaling
> file system is a problem.
>
> So it seems to me that I need to turn off automatic fsck and use a
> journaling file system. Suggestions?
>
> I read in Ward's "How Linux Works", however, that the kernel won't
> mount an ext3 file system if the journal is non-empty which could
> happen on an inadvertent power cycle. One has to first run e2fsk -fy
> to flush the journal. So it seems that I would still be susceptible to
> having the system not boot after
> an inadvertent power cycle if I use ext3 and turn off automatic fsk on
> bootup. Is this true?
>
**************************************************************************************************
> Samuel M. Smith Ph.D.
> Founder
> ProSapien LLC
> 2966 Fort Hill Road, Eagle Mountain Utah 84005-4108 USA
> 1.801.766.3527 x112 (voice) 1.801.766.3528 (fax)
> mailto: (email)
> http://www.prosapien.com/ (web)
>
I know it is far too late to answer this mail but maybe it can help other
people.
I face the same problem with a 7350 board and here is how I manage the problem.
I use the fastboot script on boot up. Fastboot mount partition 4 as read only,
so it is protedted against data corruption. I put all the config file and read
only data on the partition 4. For the data that I need to write, I convert my
partition 1 to a ext3 file system. I enable the filesystem check on every mount
(tune2fs -c1 -j /dev/tssdcarda1). I mount this partition on /mnt/data and I
write all data on that directory.
I made more the 2000 power cycle and every thing stay in place. I use Kodak SD
card somebody tell me that he have problem with cheap SD Card but it was not a
technlogic systems board.
The only problem i found with this setup it is that it take a long time before
the data is committed on the SD card (approx 5Sec) in my case it is not a
problem.
I hope it help somebody!
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