Messages in this thread | | | Subject | Re: [PATCH] roubust ext2fs against failure | From | Hirokazu Takahashi <> | Date | Tue, 17 Aug 1999 17:11:55 +0900 |
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Hello,
> Anyway this is the kind of patch that I'd really like to see > comments on from Linux big names. Either it's conceptualy
I'd like to too.
> Lastly, I bet you'd better refine the sentence: > 'Just mount ext2fs with "sync" option, ext2fs will keep > consistency of filesystem. Your filesystem would never be broken.' > in http://www03.u-page.so-net.ne.jp/da2/h-takaha/userguide.html > Do you mean that you force the controler and disk to write meta > datas in the right order to the disk, or do you assume that > there is no order problem at controler and disk cache level ?
Yes you must be right, every disk has a cache in itself.
It dosen't cause any problems when it happens to crash _not_ depeding on power-failure, all metadata on disk-cache (which is in the disk) will be write to the disk.
A problem is a crash depeding on power-failure. Some disks may keep the order, some may try to flush all disk-cache, others may not do that might cause little corruption.
I think journalling filesystem like XFS has the same problem. Writting order of "journal" and "metadata" on disk-cache to real-disk might be changed in some situation, it would cause a filesystem corruption which can't be detected at journalled recovery after a crash.
It seems to be not good idea to configure disk-cache as write-through-cache that leads a poor performance. Is there any cool solution?
Regards, Hirokazu Takahashi
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