<html><body><div>Hmh,</div><div><br></div><div>I'm not 100% sure, but a lot of people made good experience with JFFS2.</div><div><br></div><div>Is it that hard to get a log structured file system power fail safe?</div><div>Either the end or "commit" block was written or not?</div><div><br></div><div> Peter</div><div> <br><br>On 18 Apr, 2011,at 03:52 PM, Pavel Machek <pavel@ucw.cz> wrote:<br><br></div><div><blockquote type="cite"><div class="msg-quote"><div class="_stretch"><br>
Hi!<br>
<br>
> > > did the ARM Linux 2.6 kernel map the kernel memory in pages in the past?<br>
> > > Or was the memory always mapped in sections?<br>
> > ><br>
> > > I still have to chase a potential memory corruption. The rootfs is located on<br>
> > > a SDcard and gets corrupted even when the filesystem test programs write to<br>
> > > different partitions.<br>
> > > The test scenario includes several dozen or even hundreds of warm and cold<br>
> > > boot sequences, file system write tests with sudden soft resets. It's a large<br>
> > > embedded project with a lot of drivers and the fact that always the rootfs and<br>
> > > often the superblock gets damaged let me think of a memory corruption.<br>
> > ><br>
> > <br>
> > Sorry, I don't want to be obvious, but you mentioned sudden resets<br>
> > while writing, which is almost always going to wind<br>
> > up as fs corruptions, with the severity depending on the level of<br>
> > caching the system is doing to the writes.<br>
> > How are you mounting your rootfs and what file system are you using?<br>
> > What sort of corruptions to the super block are you seeing?<br>
> <br>
> If everything is implemented correctly, that depends on the type of<br>
> filesystem, block layer and storage. Some are explicitly designed to<br>
> be safe against sudden reboots and power failure - which is an<br>
> important feature of systems where removing the power is how they are<br>
> turned off at night.<br>
<br>
...but note that no existing filesystem is safe on media such<br>
as usb sticks, SD and CF cards...<br>
<br>
-- <br>
(english) <a href="http://www.livejournal.com/~pavelmachek" _mce_href="http://www.livejournal.com/~pavelmachek">http://www.livejournal.com/~pavelmachek</a><br>
(cesky, pictures) <a href="http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html" _mce_href="http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html">http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html</a><br>
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