Messages in this thread | | | Date | Mon, 19 Mar 2001 15:19:37 -0500 (EST) | From | William T Wilson <> | Subject | Re: Linux should better cope with power failure |
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On Mon, 19 Mar 2001, Otto Wyss wrote:
> inactivity. From the impression I got during the following startup, I > assume Linux (2.4.2, EXT2-filesystem) is not very suited to any power > failiure or manually switching it off. Not even if there wasn't any > activity going on.
What data, if any, did you lose?
While fsck complains loudly when the system comes back up, 9 times in 10 no data is actually lost during a power loss. e2fsck is really good at recovering damaged filesystems.
> How could this be accomplished: > 1. Flush any dirty cache pages as soon as possible. There may not be any > dirty cache after a certain amount of idle time.
Mount the filesystem synchronously to accomplish this. It will prevent the kernel from using a write cache basically. It will ensure that if a write operation completes, then the data will be physically on the disk afterward.
> 2. Keep open files in a state where it doesn't matter if they where > improperly closed (if possible).
The way to do this is to use a highly reliable filesystem, such as ext3fs, Tux or ReiserFS. These filesystems guarantee that metadata is consistent at all times.
> 3. Swap may not contain anything which can't be discarded. Otherwise > swap has to be treated as ordinary disk space.
I can't think of a case where the contents of swap matter in any way for recovering from a power failure.
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