Trouble with raid and lvm on Ubuntu Dapper

I am not sure why and how, but I fixed it :-)

• I use software raid (mdadm) and do NOT use lvm (but lvm is installed automatically with Ubuntu Dapper Server Edition).
• I have an mdadm.conf file like this:
  # cat mdadm/mdadm.conf ARRAY /dev/md7 level=raid1 num-devices=2 UUID=cada920:4eca7627:5412f973:b46b1baa ARRAY /dev/md6 level=raid1 num-devices=2 UUID=8f380fb:d10815fd:be8db44d:e572eaf7 ARRAY /dev/md8 level=raid1 num-devices=2 UUID=59808df:2a081aeb:3e212539:9766f1e0 ARRAY /dev/md5 level=raid1 num-devices=2 UUID=ecdcf44:c83a999a:afab4c83:46c1829a ARRAY /dev/md2 level=raid1 num-devices=2 UUID=5c6a4dd:999cbc80:ac49c25d:4c2489b8 ARRAY /dev/md1 level=raid1 num-devices=2 UUID=d07eae6:e4c76e60:371344cd:17049a8e ARRAY /dev/md0 level=raid1 num-devices=2 UUID=ae444d6:d69a6c47:6a3532a6:2386ac95 DEVICE /dev/hda* /dev/hdc*
• After booting, md0, md1, and md2 are created and mounted perfectly. However, two extra devices are created (and not mounted because they are not in fstab): md3 and md4.
• with cat /proc/mdstat. the device 5 - 8 are created in a strange way:
  md8 : active raid1 dm-3[1] dm-2[0] 70356544 blocks [2/2] [UU] md7 : active raid1 dm-1[1] dm-0[0] 9767424 blocks [2/2] [UU] md6 : active raid1 hdc8[0] hda8[1] 70356544 blocks [2/2] [UU] md5 : active raid1 hdc7[0] hda7[1] 9767424 blocks [2/2] [UU]
  So, md8 and md6 are equal; so is md5 and md7. Please note that the devices of md5 and md6 are hda/hdc as it should; but md7 and md8 are using 'dm-1, dm-0, dm-3 and dm-2' which is strange (to me).
• I disabled the lvm boot script in /etc/init.d, but to no avail.
• after stopping /dev/md3 - /dev/md8, and then assembling them again using
  mdadm --assemble --scan
  the devices where created as should:
  md8 : active raid1 hdc8[0] hda8[1] 70356544 blocks [2/2] [UU] md7 : active raid1 hdc7[0] hda7[1] 9767424 blocks [2/2] [UU] md6 : active raid1 hdc6[0] hda6[1] 48829440 blocks [2/2] [UU] md5 : active raid1 hda5[0] hdc5[1] 5855552 blocks [2/2] [UU]
• after the next boot, everyting was a mess again, but md3 and md4 where created (altough they are not in mdadm.conf !)
• I modified mdadm.conf and fstab, to now use devices md3 - md6 instead of md5 - md8
• after next reboot, all was fine, and no weird 'dm' devices where created anymore.

I don't know why or how, like I said, but it seems to me it's a bug because the startup scripts don't seem to follow what is in /etc/mdadm.conf

Thanks too Frogzoo at #ubuntu for thinking together with me.

See also: https://wiki.ubuntu.com/UdevLvmMdadmEvmsAgain

Zentyal/Ebox, slowness, and WDxxEARS Advanced Format

• Zentyal (formerly named Ebox) is an Ubuntu based Small business server that is easy to configure and in my opnion a real breakthrough in Ubuntu-based small business servers. Unfortunately, I had a bit of bad luck (or lack of information) when I installed my first two servers for clients on Curaçao. The server was very, very slow, up to the point where a simple ssh login took 2 minutes and in one case the install halted halfway. I spent many hours trying to troubleshoot the problem and meanwhile I had to revert to webmin or some other solution.


• The problems are described in the following posts on the Zimbra forum:
  http://forum.zentyal.org/index.php?topic=3697.0
  http://forum.zentyal.org/index.php?topic=4212.0
  http://forum.zentyal.org/index.php?topic=3968.0
  http://forum.zentyal.org/index.php?topic=3427.0
  http://forum.zentyal.org/index.php?topic=4273.0
  and most notably
  http://forum.zentyal.org/index.php?topic=5724.0


• Unfortunately, the forums didn't help much. After many days of frustration, I decided to buy support, which cost 390 EUR. I've never paid for support before in my life and I hope I don't have to do it again. Although the team at Zentyal did their best to help me, they didn't really succeed. Finally, after swapping out all hardware except the harddisks, I bought a new harddisk, although there where no harddisk errors reported and SMART status was okay.


• Then it hit me like a brick. I typed in the model number of my Western Digital Caviar Green WD10EARS and what do you think - hundreds of posts about how this harddisk uses Advanced Format and how that gives loads of problems. Google for yourself: any WD of the EARS series has this problem. My new disks where of the EADS series and after copying all the data (which took ages) and reinstalling the server, the server was flying! Normal load, normal speed, everything was fine.


• The problem lies in the alignment of sectors on the EARS drive. More information on the Advanced Format can be found here and here.


• After I repartitioned the EARS drives by hand, I installed a new server with these disks, and the server was as fast as it should be. Wrong alignment of the EARS drives really really slows all disk I/O down.


• Newer versions of parted should detect AF automatically and so I hope the Zentyal team will put the newer version of parted into their installer. Also, when giving support, a simple
  
  
  hdparm -i /dev/sd?|grep EARS
  
  
  would make the problem clear right away. A pity that the team at Zentyal didn't know that and I hope this information will be integrated in their knowledgebase.


• All in all, I find Zentyal a great product that really fills a niche in the small business server market. I am happy with the server now that the slowness problems have been solved.

Ebox 1.4 and HP Color LaserJet 2600N

• Follow instructions here: ubuntuforums.org, except the last step.
  
  
  $ wget -O foo2zjs.tar.gz http://foo2zjs.rkkda.com/foo2zjs.tar.gz
  $ tar zxf foo2zjs.tar.gz
  $ cd foo2zjs
  $ make
  $ ./getweb 2600n # Get HP LaserJet 2600n .ICM files
  $ sudo make install
  $ sudo make cups
  
  
  Now go to Ebox -> Printer Sharing -> Add Printer
  And go find the HP -> Color Laserjet 2600N. It will now have a driver (foo2hp). The next page you can select stuff:
  
  "Color Mode" = Color
  "Bits Per Plane" = 2
  "ICM Color Profile" = (something like hpclj2600n-0.icm)