On Friday 31 December 2010 22:11:37 Volker Armin Hemmann wrote: > reiser4 is fully atomic. A transactions happens completely or it doesn't. > > Unlike ext4 or btrfs or xfs. > > reiser4 also uses barriers (the others use them too, but), when barriers > are not available for some reason or another, it complains in dmesg and > goes into sync mode. > > This combined makes it pretty robust against power failures. You won't get > the good old xfs/ext4/btrfs problem that a rename can end with two useless > empty files.
I read what Volker is saying and it sounds impressive from a fs design perspective, but my experience does not concur with it. I have a had a power cut (run out of battery) and the fs got corrupted. :-( This however may not be a conclusive finding. I was running reiser4 for about a year on my laptop. Unfortunately, I have a had a large number of fs corruptions, most of which appeared to be random. The last one just before Christmas proved to be fatal and unrecoverable with fsck.reiser4. I could try to blame the disk, but the MSWindows ntfs which I dual boot to from the same disk never failed or corrupted (admittedly though it has seen hardly any use). I have to say that when it did run without corruption reiser4 is an exceptional fs in terms of performance. With the exception of mounting large partitions which takes some time, I don't think anything else I've tried comes close. If I were to build a desktop which unlike a laptop is not bounced around when commuting on trains and what not, I would probably try it again (because I have a niggling suspicion that the cause of my problems might have been a mechanical reason). Either way, I can say with some certainty that power cuts and running out of space on a partition brought about fs corruption with reiser4. I have now moved all but one of my partitions to ext4 and will wait to see what happens with that, but 11 months on reiser4 has left a bad taste in my mouth. Historically, I have mostly used reiserfs and xfs. Reiserfs is in my experience very reliable and easily recoverable and I can assuredly echo Alan's findings. Some years ago I had a faulty memory controller which would hard lock an old desktop. At least once a day (typically in the middle of an emerge, or updatedb) it would crash badly and I would have to pull he plug. In as many as 4 years I must have had hundreds and hundreds of hard reboots. I vaguely recall one or two fs corruptions on only one or two partitions. reiserfsck did recover the fs every single time without major drama. If bleeding edge performance is not an issue I would recommend reiserfs to mitigate the risk from powercuts. -- Regards, Mick
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