lindner

Since you missed this before...

Originally shared by Theodore Ts'o

Phoronix, alas, has perpetrated another example of irresponsible journalism.   I won't dignify said article with a web link, since I don't want to reward them with more ad hits.  So I'll link to the original Ubuntu Launchpad report, and include the comment I just made there:

Those specific fsck corrections --- fixing the number of free blocks and the number of free inodes --- is completely normal and is purely a cosmetic issue. There is nothing to worry about here.

What is going on is that ext4 no longer updates the superblock after every block and inode allocation; that causes a wasteful write cycle to the superblock at every single journal commit, and it also is a SMP scalability bottleneck for larger servers (i.e., with 32 or 64 CPU's). To fix this, we no longer update these values in the superblock every time we allocate a block or an inode. Instead, we only update these values when we unmount the file system, mainly for cosmetic purposes so that dumpe2fs shoes the correct number of free inodes and blocks, and at mount time we calculate the total number of free blocks and inodes in the file system by summing the the free blocks/inodes statistics for each block group. So in fact, ext4 does not depend on the correctness of the values in the superblock, but it does try to update them on a clean unmount.

In e2fsprogs commit id 2788cc879bbe6, which is in e2fsprogs 1.42. 3 and newer, we changed things so that e2fsck -n would not display this as something "wrong". However, we still do show this as something that we "fix" when running e2fsck -y or -p, since in fact it is a change to the file systems. See: http://git.kernel.org/?p=fs/ext2/e2fsprogs.git;a=commit;h=2788cc879bbe667d28277e1d660b7e56514e5b30

No one else has complained or noticed up until now, because other distro's apparently are capable of doing a clean shutdown allowing the file system to be unmounted cleanly. Ubuntu, unfortunately, is incapable of reliably doing a clean shutdown even when users request it, which is why Ubuntu users are seeing this behavior much more frequently, and apparently some people have panicked as a result. Sigh....

----

I will say that it is extremely irresponsible of Phoronix to make a big deal about this this before giving anyone knowledgeable (which unfortunately  does not include any Ubuntu kernel engineers, since as far as I know they don't have any file system specialists on staff) to comment on the bug.  No one from Phoronix even bothered to contact me to tell me they were posting this story, or to ask me for a comment.  I had to find out about it when someone asked me to comment on Google+.

However, from the perspective of trying to send as many ad clicks as possible to their web site, they are doing a heckuva job....

#paullindner #paullindner

Please welcome Baron von Luxxury to Google+! Add him to your music or DJ circles today and check out his new album which you can snag for free for one week only. (though it's definitely worth paying for..)

Dubbed the "Post-Post-Synthpop King" by the LA Weekly, Baron Von Luxxury seeks to erase the lines between high and low art by merging elements of innovative dance music with the idiot immediacy of classic pop.

I had the good fortune to work with him at Red Hat before he became famous. Some day I'll tell some stories about hairnet banner ads and psychic web-sites trying to go legit by offering linux phone support. (yes! really!)

Originally shared by Baron von Luxxury

Happy Day After Valentines Day, My Darlings!

Please download my new album The Last Seduction. For Free. It just came out today. And for 1 week only you can download it for any price you want, including $0. I honestly don't care how much or even if you pay, I just want you to have the music! Please. Just take it.

http://baronvonluxxury.bandcamp.com

#paullindner #paullindner

Until everything in the world is in the cloud this works well for getting the bits from the linux file server in the garage to the Google TV in the living room.

Plus it uses freebase.com data to enhance your content in new and interesting ways.

#paullindner #paullindner

Hey look, it's the Fedora Project! On Google+

Check out Fedora 16 if you're into Linux distros. I just finished upgrading the home server last night and it's running smooth. (even if systemctl reminds me way too much of solaris SMF)

Fun fact: I've been upgrading the same system image since Red Hat 6.0. No reinstalls.. and since I never had a CD/dvd all upgrades were via rpm/yum.

#paullindner #paullindner

Couldn't agree more...

Originally shared by Brad Templeton

When I saw the news about Steve Jobs it was a shock. But the news that Dennis Ritchie has died was much more like a blow. I didn't know him super well, we attended Usenix together for many years, but he was mostly a quiet man, not the sort to seek the limelight.

Dennis was instrumental in two things -- the C language and Unix -- which are the foundation of almost all the computing in the world today. Certainly much of C came from its predecessors like B and BCPL, and many things in Unix from its predecessors like Multics, but these two focal points were where all of 60s and early 70s computer science came together, and spread out. Of course Linux and MacOS and Android are very direct descendants of Unix, but even Windows is filled with ideas from Unix.

Far more than Steve Jobs, pretty much all your computing is based on Dennis' work. Last week Google noted Jobs at the bottom of the home page, a very rare honour. But Dennis Ritchie would be even more deserving of it.

#paullindner #paullindner

It appears that Fedora 12 moved to a new boot init system called dracut.  Sadly due to a number of odd circumstances this has caused me much pain.  Here's my basic config

# dmraid -r 
/dev/sdd: sil, "sil_aiabafajfgba", mirror, ok, 488395120 sectors, data@ 0
/dev/sdc: sil, "sil_aiabafajfgba", mirror, ok, 488395120 sectors, data@ 0

fprintf(stderr, Name ": WARNING %s and %s appear"
" to have very similar superblocks.\n"
" If they are really different, "
"please --zero the superblock on one\n"
" If they are the same or overlap,"
" please remove one from %s.\n",
devices[best[i]].devname, devname,
inargv ? "the list" :
"the\n DEVICE list in mdadm.conf"

Drats! the mirrored fake raid had already mangled my second drive by duplicating the superblock!  Plus since all this was going on in dracut I couldn't fix it.  So I removed the nodmraid option in grub during boot and dug a little deeper. I found that I could keep dracut from doing all this nonsense by adding the following kernel options:

rd_NO_MD rd_NO_DM nodmraid

mdadm --zero-superblock /dev/sdd1

And then rebooting (again!)

# mdadm --manage /dev/md_d0 --add /dev/sdd1

To get rid of the false-positive fake raid setup I found that you can do this with the dmraid tool itself:

[root@mirth ~]# dmraid -E -r /dev/sdd

Do you really want to erase "sil" ondisk metadata on /dev/sdd ? [y/n] :y

[root@mirth ~]# dmraid -E -r /dev/sdc

Do you really want to erase "sil" ondisk metadata on /dev/sdc ? [y/n] :y

#dmraid #linux #mdadm #raid

#kitty #luxxury #redhat