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I understand that any files being written to during power loss can get corrupted, but is it possible for an entire ext3 filesystem to become corrupted during a power loss event? If so, how?

Thanks!

cat pants
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1 Answers1

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TL;DR: it is not likely with the default mount options but it still may happen. If you tune the mount options and set unsafe flags, yes it is possible.

ext3 is a journaled filesystem meaning that it is less likely to be corrupted by a hard power-off than ext2 for instance which is not using journaling.

That being said, it is not impossible for an ext3 partition to be corrupted. In particular, data stored in the cache when the power-off happen will be lost. As no checksum is done on the journal is made on ext3, it can still lead to significant problems, see Wikipedia for more information (references 32, 33 and 34).

Also, ext3 mode can be changed at mount time, some options being more dangerous than others, see ext3 documentation. If journaling is disabled, of course, the file system will be vulnerable to corruption on power-off.

One last note: corruption of an "entire filesystem" is very unlikely for any filesystem. If you exclude particular and pathological cases (power-off during filesystem check, etc), no filesystem will ever operate manipulations on the whole filesystem at once. Therefore, the usual corruption issues are for some inode of your partition, not all the data.

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Thomas Moulard
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  • Thanks for the fantastic explanation. I definitely understand that it would be difficult to lose all data (unless there is a head crash or similar) as changing data on the whole disk takes quite some time. – cat pants May 15 '14 at 21:03