On Thu, 28 Oct 2004 03:51, ngc4013@xxxxxxx wrote: > In the past I too have lost data due to power outages and ext2 or ext3 > filesystems, but now I have exclusively been using reiserfs for about 5 > years now on all my boot drives and on my RAID boxes. I typically see >25% > speed increase when writing out large files and accessing them for > processing purposes and have had zero data loss. Reiserfs4 is looking like > it will provide >60% increase in file writes and a boost in file reads... > wish it was ready for prime time. When I was last using ReiserFS it was impossible to do a full fsck of a file system that was mounted read-only. This meant that certain classes of error which on Ext2/3 could be fixed by a regular fsck run required that the machine be booted from other media. This could be fixed by having reiserfsck in the initrd, but AFAIK no-one has done this. Last time I spoke to Hans about corrupted ReiserFS file systems causing system crashes (not orderly panics) through access to random memory he didn't seem to consider it a big deal. Checking all data structures decreases performance. The ext2/3 developers seem to have a goal of never having a corrupted file system kill the entire machine. Reiser3 has some annoying design deficiencies. One of which is that you can't use a ReiserFS file system to store an image of another ReiserFS file system. This means that for example if you have a file system that is corrupted beyond the ability of reiserfsck to repair you must make sure that you put an image of it on an ext2/3 file system if you want to keep a copy to test new versions of reiserfsck. Otherwise a fsck of the file system which contains the image file will make it contain both sets of files, here's an example: mkreiserfs /dev/hda6 mount /dev/hda6 /mnt cp ~/foo /mnt umount /mnt mkreiserfs /dev/hda7 mount /dev/hda7 /mnt dd if=/dev/hda6 of=/mnt/fs-image umount /mnt reiserfsck /dev/hda7 mount /dev/hda7 /mnt find /mnt -name foo (reveals that the file is there, it's escaped from fs-image). ReiserFS performed much better than ext2/3 for file creation, deletion, and random file stat operations before directory indexing was added. Even afterwards ReiserFS seemed to have a performance benefit in these areas but it was much smaller. ReiserFS performed significantly worse than ext2/3 for writing small amounts of data if you don't mount with notails. Mounting with notails removes one of the advantages of ReiserFS which is better space efficiency for small files. ReiserFS performed very poorly when compared to ext2/3 for writing data to files a byte at a time when I last benchmarked it. Also creating a large hole in a file has given terrible performance for ReiserFS (seek 10G and write 1 byte and the kernel will use some minutes of CPU time and block everything else). One minor bug I found on ReiserFS which AFAIK has not been fixed is that if process A is in a loop of "write 1 byte to file and seek to 0" then another process which opened the same file read-only would not be able to close it (the close would block forever). There is probably some good potential for DOS attacks in that. I like Hans and I like ReiserFS. But the situations in which I use it are limited for the above reasons. Also ReiserFS can not be used as a root file system for SE Linux which is another reason for me not to use it. -- http://www.coker.com.au/selinux/ My NSA Security Enhanced Linux packages http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/~russell/ My home page