journaling filesystems and SD cards
 

At the moment I am using a 16 GB class 4 SD card as the main drive on my netbook. It's formatted with ext4; in an effort to reduce wear and improve performance, I disabled the filesystem's journal. As far as performance and battery life go, that works extremely well.

However, I'm a little concerned about filesystem integrity without a journal. fsck times shouldn't be a problem, but how likely is irrepairable filesystem corruption in the event of an improper shutdown?

I would expect non-journaling filesystems to be safer than on a hard drive (since there's no hardware write cache). But if so, how much safer?

Make a sample build. Then at various stages of work and non-work hit the power and see how bad it can get or not.

Having been in your shoes but using a ext2 file system and Puppeee as a frugal install.

On improper shutdown. The card would fill with writes and be unbootable. I could fix this though by leaving the card in. Booting any other Linux distro with Gparted on it via another
pendrive. Open the sd card in gparted. Unmount it first. Then right click and pick check
and then apply. When done. Shutdown and pull the pendrive. Reboot into my fixed Puppeee sd
card. Nothing was lost.

Thanks... The answer so far seems to be that it's reasonably safe, provided you can get fsck to work (or fsck from a live medium). Which is cool, because even a cheapo SD card gives very good performance.

Edit: actually it turns out you can use a small journal (less than 16 MB or thereabouts) without serious performance impact, so that's what I'll do, in the interest of stability.

Not sure I suggested reasonably safe. Test it for yourself and decide.

Safe is common backups, ups and any other feature to include improved filesystems.

Yeah, I got some nasty filesystem errors after suspending, and had to run fsck from a live CD. Journaling it is.

Edit: no, journaling doesn't make a difference, and the filesystem is actually clean and intact. I think this is some kind of issue with the mmc drivers that crops up on suspend.

A well hidden message in it?


Suspend is not power off. Suspend should never mess up the filesystem no matter what it is.