I ate in a place where they sell Ubuntu Cola! Not related at all with Ubuntu OS, except for the name (and its meaning).
I usually don’t drink cola drinks, so to me it tastes like any other cola. But it’s a fair trade product, so why not drinking Ubuntu cola instead of big corporations ones?
Apple recently introduced the new version of iTunes: iTunes 10. For those, like me, who are using Firefly to broadcast their music on their local network, you may have seen that iTunes 10 does not show the content of your remote playlist anymore 
. The bad news is that a lot of commercial products are using it (especially NAS devices like Drobo…).
Someone started a thread about that on Apple’s forum: http://discussions.apple.com/thread.jspa?threadID=2564925
One guy says to have a look to forked-daapd which is a full rewriting of Firefly. So I did. On my Debian box, a package is available in “testing”:
$ sudo apt-get install forked-daapdChange the directory where the music is in /etc/forked-daapd.conf, restart and that’s all. Then go to iTunes, the shared library should be visible and filled with your music!
Since Firefly is a dead project (no activity for a while), everybody using it should migrate to forked-daapd.
Note: this is my 100th post on this blog!
Today I was quite disappointed when I saw that my RAID-5 array had suddenly lost 2 out of 4 drives. As you may know, losing 1 drive on RAID-5 is OK, losing 2 is not ok at all, it usually means that you have lost all your data.
In fact, my failure today was due to some electrical problems. If you are following this blog you know that my RAID drives are plugged to the server (Debian GNU/Linux) using USB, which is an extremely bad idea (don’t do that at home 
). And to add more on my stupidity, in order to reduce power consumption I changed my hard drives to laptop hard drives and have them powered through the USB hub… which was not plugged to the UPS. So today there was a power failure at home and since the server’s USB was not providing enough power, two drives went off.
Since nothing was being written when it occurred, I know that the content on every drive was still good, but mdadm reported the array as degraded and reading was not really possible anymore.
So, what to do in that case? From what I have seen, the first thing is to stop the array, then to try to reassemble it with various options (but do not try to re-add the “failing” drives). Obviously I did some mistake… So, if at some point mdadm --assemble with any kind of options does not work, re-creating the array might be your last solution. At least it worked for me.
But be careful, when creating the array, you have to provide the same options (chunk size…) as it was before, and you have to keep the drives in the SAME ORDER. And when you have drives on USB, the order is a bit random (maybe I should have looked at each disk’s UUID and write the order somewhere).
So I re created the array with the following command (DON’T FORGET “—assume-clean” otherwise mdadm will start re-synchronizing your disks and it’s something you may not want):
mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 --assume-clean /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1After doing so… it was still not working. Why? Because I didn’t gave the right disk order! With 4 drives I have something like 24 different possibilities. How to find out if it’s the right one? Well, that’s quite easy, you should be able to mount the disk . Doing a fsck might also be a good idea (don’t forget the -n option as you don’t want to write on the drive until you are sure that it’s the correct order).
I was quite lucky since I found the right one on the second try.
Last year I bought a fit-PC in order to replace my old router (which was a desktop PC). This year I bought a fit-PC2 to replace my home server (which was a big fat computer).
This time my needs were a bit different than the ones for my router. I was looking for a low power consumption device with at least 512 MB of RAM, fast enough to read videos (I may use it as a HTPC in the future), fan-less and of course, it must work with Linux.
So I end up with Compulab’s fit-PC2. Here are the official specs:
Several flavors are available (with WiFi, without hard drive, with an Atom Z510 CPU…).
I tried the pre-installed Ubuntu but it’s an old version (8.04). Anyway, it was working quite fine. For video playback only MPlayer was using hardware acceleration provided in fit-PC2. I played Sita Sings The Blues on it, it works wonderfully (the movie is a Full HD (1920*1080), 4.12 GB file (I was hardly able to read it on my MacBook)).
But I don’t really want to use Ubuntu. If I want a *buntu linux I would install Kubuntu instead, anyway I installed Debian. Here is the beginning of my troubles.
First, I’m using Debian’s “testing” version, which proved to be quite stable so far. Except with the new 2.6.30 Linux kernel which froze my VIA C7 powered Dedibox and is behaving weirdly on the fit-pc2. I don’t know if the problem is in linux kernel, gcc, debian but installing 2.6.30 kernel was not a good thing on my debian boxes. I’m using the fit-pc2 remotely (ssh, music streaming, time machine backups ) and from time to time it stops to respond, but if I hit a key on the keyboard, network operations resume very weird. A problem in power saving code? a deadlock which resolved itself when a new interruption is raised? No idea, I’m clearly not competent in that domain. Easy solution: revert to 2.6.26 kernel.
Second problem: drivers. The graphic chipset used is an Intel GMA500. Even if Intel recently helped the Open Source community by giving specifications of its chipsets, they didn’t for that one (because it’s not really an Intel one, it was developed by PowerVR (and they are much less cooperative)). Somehow Compulab/DeLL/Ubuntu managed to get a partly open source driver with hardware acceleration (that part is still proprietary), but according to various websites, the driver is crappy and not well maintained (but it looks like some people are trying to make that better). So, for now, hardware acceleration does not work easily on Debian. I hope it will work soon.
It seems that it consume a bit more than expected (my watt-meter is a cheap one, I’m not sure how reliable it is), or maybe figures on fit-pc2 website were given for an Atom Z510.
Note: the case can be very hot.
fit-PC2 is a nice bit of hardware, but if you are going to install an alternative BSD/Linux operating system, you have to know that you may get some troubles with video drivers (if you need nice graphical interface).
I’m very lucky those days. 2 weeks ago my laptop hard drive died. Today I lost a drive in my RAID array.
Few month ago I moved my RAID array from SATA to USB but USB components seems to be of lower quality than SATA ones. So from time to time I see some “USB reset” when reading/writing a lot of data, fortunately it only stop transfers for a few seconds before resuming.
Today my server was fsck‘ing the array when a disk failed badly. It looks like the external drive’s USB controller crashed. The disk was not visible anymore from my server (I had to manually restart the external drive).
Since it’s a RAID 5 array, everything was still working fine, in degraded mode:
$ sudo mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Sat Jan 19 17:03:46 2008
Raid Level : raid5
Array Size : 1465151808 (1397.28 GiB 1500.32 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 4
Total Devices : 3
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Wed Jul 22 22:16:04 2009
State : clean, degraded
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : 02918692:35547ed8:ccb6a325:e4cda885 (local to host seth)
Events : 0.3774
Number Major Minor RaidDevice State
0 8 65 0 active sync /dev/sde1
1 0 0 1 removed
2 8 81 2 active sync /dev/sdf1
3 8 33 3 active sync /dev/sdc1Then adding back the missing drive:
$ sudo mdadm --manage /dev/md0 --add /dev/sdd1
mdadm: re-added /dev/sdd1
$ sudo mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Sat Jan 19 17:03:46 2008
Raid Level : raid5
Array Size : 1465151808 (1397.28 GiB 1500.32 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Wed Jul 22 22:19:23 2009
State : clean, degraded, recovering
Active Devices : 3
Working Devices : 4
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 64K
Rebuild Status : 0% complete
UUID : 02918692:35547ed8:ccb6a325:e4cda885 (local to host seth)
Events : 0.3780
Number Major Minor RaidDevice State
0 8 65 0 active sync /dev/sde1
4 8 49 1 spare rebuilding /dev/sdd1
2 8 81 2 active sync /dev/sdf1
3 8 33 3 active sync /dev/sdc1Now I can monitor the slow process of rebuilding the array:
$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1[4] sde1[0] sdc1[3] sdf1[2]
1465151808 blocks level 5, 64k chunk, algorithm 2 [4/3] [U_UU]
[>....................] recovery = 2.2% (11184896/488383936) finish=661.5min speed=12019K/sec
unused devices: <none>At least 11 hours to rebuild!!! So, for people as stupid as me: don’t use USB for a RAID array if you are not obliged to, it’s not very safe and it’s a bit slow.
In a previous post I explained that I configured my Debian GNU/Linux server to act as a Time Machine server.
The purpose of Time Machine is to backup your Mac and to allow you to retrieve some files you deleted or to restore your system. Last week my MacBook’s hard drive suddenly died without a warning. Since I was moving in my new apartment, the last backup was few days before, but at least I had a quite recent backup.
The question was: does Time Machine will allow me to restore my backup as expected?
I bought a new hard drive, plugged it, boot on Mac OS X install DVD, selected Utilities/Restore system from backup… then nothing. No backup listed and the “Connect to remote disk” is grayed/disabled .
I was a bit disappointed. I launched the terminal and tried to manually mount the remote backup but I failed. This was the good solution, I just didn’t know the right command to mount a remote apple volume. After googling a bit (thanks to my iPhone) I found the right instructions:
# mkdir /Volumes/backup
# mount_afp afp://login:password@hostname/volumename /Volumes/backup
Then relaunch the “Restore from backup” utility, the remote volume was now listed. Just had to select and start waiting (restoring the system may be quite long).
I blogged about how to create a RAID-5 array with GNU/Linux in a previous entry.
So my home server is running a 4 disks array (about 500 GB each, for a total of 1.5 TB available). I used SATA disks plugged in the server. For some silly reasons I wanted to move the disks out of the server and plug them using a USB interface (no, not a eSATA one, USB (I told you, it’s silly, but it could have been worse, like creating a floppy RAID array)).
I bought 4 Icy Box enclosures and a USB hub. Shut down the server, move the disks into the external enclosures, plug everything (lots of wires), switch on the server, cry.
As quite expected, it didn’t work right away. My Debian server stopped on a maintenance shell, complaining that it was not able to check /dev/md0 (the array).
No problem, I tried a simple command:
mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1
Array assembled, exit the shell, Debian finished booting, everything works. But, in doubt, I did a reboot. Again, array not recognized. After a bit of googling and man reading, I tried the same command with a little option added:
mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 --update=homehost
Not really sure about what it did, but after rebooting, the array was recognized and assembled automatically.
So YES, you can change the controller interface used to plug your disks in an RAID array.
What about speed? Well
high speed is obviously not the purpose of this experiment (but at least it’s > 30 MB/s in continuous read).
What about reliability? Well it’s Raid-5 so I might have to rebuild from time to time. So far I only get some USB reset events so transfer stall during ~20 seconds then resume. Of course I get more resets when doing a big transfer.
Here is a quick tutorial to build your own mail server using a Debian GNU/Linux.
Configuring its own mail server can be fun, but remember that there are a lot of bad guys on the internet. I’m no expert on mail server configuration, don’t forget that you must not allow relaying mails to domains you don’t own and from people you haven’t authenticated in order to avoid spam relay. Of course, keep your softwares (operating system, mail server, etc.) up to date in order to keep your computer safe from being cracked.
I have a domain name (desgrange.net as you can see) and I would like to use it for my mails. It’s not that I don’t trust service providers, but I would like to be in charge of the mail server configuration (so I would be able to tune it as I want).
For instance, I want to be able to send mails using SMTP over SSL and retrieve emails using IMAP over SSL.
For those tasks I chose:
In this tutorial I assume that I’m installing a mail server for domain example.com on a computer named mailserver. Allowed users are the standard unix users created on the mail server.
First make sure that your DNS has your MX record pointing to your mail server. See with your domain name provider for that part. I’m using OVH so I did it on their website (which sucks a bit for that).
Postfix is a well known SMTP server. As a lot of mail servers, it has several hundreds parameters, but here, all of them have good default values, so we just need to change some of them to get it working like we want. Let’s start with postfix installation:
$ sudo apt-get install postfix
-> General type of mail configuration: internet with smarthost
-> System mail name: example.com
-> SMTP relay host: <blank>Now we need to install the authentication system saslauthd.
$ sudo apt-get install sasl2-bin libsasl2-modulesAs told by the installation process, to enable saslauthd, edit /etc/default/saslauthd and set START=yes.
To tell postfix to use saslauthd, create a file /etc/postfix/sasl/smtpd.conf containing:
pwcheck_method: saslauthd
mech_list: PLAIN LOGINAs postfix is running chrooted, to allow it to talk to saslauthd we need to move some files (or change the directory specified in OPTIONS in /etc/default/saslauthd):
$ sudo mkdir -p /var/spool/postfix/var/run/
$ sudo mv /var/run/saslauthd /var/spool/postfix/var/run/
$ sudo ln -s /var/spool/postfix/var/run/saslauthd/ /var/run/saslauthd
$ sudo adduser postfix saslPostfix is configured to run on the standard port 25 so other mail servers can transfer mails to you. This postfix process can’t use SSL only because other mail servers may not support it. So we need to start an other postfix process running over SSL, so we can use this one when we want to send an email. To allow this process to start, just uncomment the submission lines in /etc/postfix/master.cf.
Check that /etc/mailname contains your domain name. It’s used by postfix for some parameters (seems to be debian specific).
Most of postfix configuration is done in /etc/postfix/main.cf, you can edit this file directly or use the following commands:
- $ sudo postconf -e 'smtpd_tls_security_level = may'
- $ sudo postconf -e 'smtpd_tls_mandatory_ciphers = high'
- $ sudo postconf -e 'smtpd_tls_mandatory_exclude_ciphers = aNULL'
- $ sudo postconf -e 'smtpd_tls_mandatory_protocols = TLSv1'
- $ sudo postconf -e 'mydestination = $myhostname localhost.$mydomain localhost $mydomain'
- $ sudo postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated,reject_unauth_destination'
- $ sudo postconf -e 'relay_domains ='
- $ sudo postconf -e 'home_mailbox = Maildir/'
- $ sudo postconf -e 'mailbox_command ='
Line 1 tells postfix to use TLS on standard SMTP port (25) if remote server support it.
Line 2 restricts TLS ciphers to only “HIGH” ciphers.
Line 3 excludes aNULL cipher (no encryption).
Line 4 tells to use TLSv1 as protocol for the postfix over SSL process.
Line 5 list domain names for which the server will accept mails.
Line 6 tells postfix to send mails only from authenticated users or to domains postfix is in charge of.
Line 7 postfix must not relay mails to other domains.
Line 8 and 9 are for Courier which use a specific type of mailboxes.
You can have a look at the postfix configuration parameters documentation.
Courier is a full mail server but here I’m going to use only Courier’s IMAP server component. Installation:
$ sudo apt-get install courier-imap-ssl
-> Create directories for web-based administration?: noBy default IMAP and IMAP over SSL processes are started but I don’t want the first one. To disable the standard IMAP process, set IMAPDSTART to NO in /etc/courier/imapd.
Some parameters have to be changed for the IMAP over SSL process, edit the file /etc/courier/imapd-ssl and set the following values:
(…)
IMAP_TLS_REQUIRED=1
TLS_PROTOCOL=SSL23
TLS_STARTTLS_PROTOCOL=SSL23
TLS_CIPHER_LIST=HIGH
(…)For TLS_PROTOCOL and TLS_STARTTLS_PROTOCOL I use SSL23 because I’m using Apple Mail and it does not handle TLS very well. If you use a mail client supporting TLS, replace SSL23 with TLS1.
First we need to restart everything:
$ sudo /etc/init.d/saslauthd restart
$ sudo /etc/init.d/postfix restart
$ sudo /etc/init.d/courier-authdaemon restart
$ sudo /etc/init.d/courier-imap restart
$ sudo /etc/init.d/courier-imap-ssl restartIf you type sudo netstat -lntp you should see something like that:
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 12718/master
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 12718/master
tcp6 0 0 :::993 :::* LISTEN 12440/couriertcpdThere are two processes for postfix (master on ports 25 and 587 (SSL)) and one for courier on port 993.
Create your mailbox. You may want to initialize your own mailbox directory on the server:
$ maildirmake ~/MaildirI didn’t say anything about SSL certificates, you need certificates for all your SSL connections, here some default ones are created, but when you connect with your mail client, it may complain about the certificate not being trustworthy.
It may prevent you to read/send mails (for instance I had to tell Apple Mail to trust the certificate in order to be able to send emails).
While configuring my mail server I ran in several problems, mainly due to Apple Mail, TLS and certificates. So, if you have any trouble, don’t forget to have a look at log files in /var/log/, use netstat and ps to be sure that your servers are running and listening on the right ports.
You may even try to manually connect to the IMAP server with a command like this one:
$ openssl s_client -tls1 -connect mailserver:993 -state -debugHave a look to the IMAP commands to check if it works.
Some of the errors I had:
SASL authentication failure: cannot connect to saslauthd server: No such file or directory because I didn’t had moved saslauthd files to /var/spool/postfix/var/run.imapd-ssl: Unexpected SSL connection shutdown because Apple Mail was not trusting the certificate.imapd-ssl: couriertls: connect: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number because Apple Mail does not support SSL3/TLS1 on IMAP.My father’s mail client was displaying the following error message:
Filesystem notification initialization error -- contact your mail administrator (check for configuration errors with the FAM/Gamin library)A quick solution to solve that is to replace FAM with Gamin:
$ sudo apt-get install gaminAnd to restart courier.
Some useful resources:
One great feature introduced in Mac OS X 10.5 (Leopard) is Time Machine.
Time Machine is a backup/restore system. As a lot of backup systems it creates an incremental backup. You can create your backup to an attached hard drive, a Time Capsule or an Xserve.
If, like me, you would like to backup your Mac on a Linux server, there is a solution. It’s not perfect yet, but so far (I’m using it for a week now) it’s working quite well.
I followed the instruction written on how to create a Time Machine Server on Debian (it’s in french), which is mostly a translation of this article on how to create a Time Machine Server on Ubuntu (in english).
It’s quite easy, you just have to follow instructions. Some tips:
cracklib2-dev package, I just had to install libcrack2-dev instead.netatalk package. In order to prevent that you can use the following command (see Preventing Debian package upgrades):# echo "netatalk hold" | dpkg --set-selections
I said it was not perfect because from time to time Time Machine failed while backuping, so I have to launch a new backup (ok, it’s just 2 clicks). The other problem is that my home folder is encrypted with FileVault. In that case Time Machine does not backup my home folder when I’m connected. When I logoff, FileVault do some stuff then my home folder is backuped. But now with a remote backup, the backup part is not done anymore. I have to connect with an other account and launch a backup.
Like a lot of Mac users, I’m using iTunes to listen to my music. The overall software is quite good but there are several things that are just wrong. By default iTunes is only able to read mp3 and Apple‘s own audio codecs. I convert all my CDs to FLAC because it’s a lossless and open source codec.
The other problem I have is that my MacBook has a small hard drive so I can’t keep all my music on it (especially if encoded in FLAC).
The solution is to use Firefly and have it sharing my music on my local network. The music is decoded by Firefly then sent over the network, so iTunes doesn’t have to know how to decode the original file.
Installing Firefly on Debian is quite easy:
$ sudo apt-get install mt-daapd
Then edit /etc/mt-daapd.conf in order to configure it a bit. There is also a web interface to configure Firefly, connect on your server on port 3689 with your web browser (the main thing you have to set is the directory where your music is).
Now open iTunes, you should see a Firefly share in the left panel:
Some drawbacks with this method. On iTunes you only see remote playlists, so some functionalities are not working anymore (changing songs metadata, genius, sound check, creating your own local playlist from the remote one, copying a song to your iPod/iPhone (retrieving a song in local)).
In a “professional” environment, when you are using a GNU/Linux distribution, it’s quite often RedHat Enterprise Linux.
So I was trying some stuff at work with a RHEL5. But after being installed, you need an account to the RedHat Network in order to keep your RHEL updated and install new packages.
Of course, an account on RHN is not really free. I wanted to install some softwares that were included on RHEL5 DVD but the UI for installing/removing softwares is really crappy and does not allow to change/specify RPM repositories/locations.
One way to install a RPM is using the rpm command, but when the package has a lot of dependencies, it’s nearly impossible to manage it by hand.
Yum is the tool used for updating the system and installing new softwares and it’s able to manage the dependencies between packages.
Here is a way to create a repository (in /srv/repo) with the RPMs located on RHEL5 DVD and add it to yum.
createrepo. It’s a single RPM which can be easily installed manually:# cd /<path_to_dvd_1>/Server
# rpm -i createrepo*.rpm# mkdir /srv/repo
# cp /<path_to_dvd_1>/Server/*.rpm /srv/repo # this command may not work 'as is' if there are too many files to copy
# cp /<path_to_dvd_2>Supplementary/*.rpm /srv/repo# createrepo /srv/repo/etc/yum.repos.d/local.repo:[localrepo]
name=Red Hat Enterprise Linux Local Repository
baseurl=file:///srv/repo
enabled=1
gpgchekc=0Now you will be able to install with it dependencies any of the RPMs located in your repository by typing:
# yum install <name_of_the_package>If you add some more RPMs in your repository, you need to execute again the createrepo command.
EPEL (Extra Packages for Enterprise Linux) is a repository of extra packages maintained by the community. It may contains some useful applications and adding it to yum is very easy:
# rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-3.noarch.rpmRHEL is targeting companies ready to put money into their Linux distributions, so they manage to get money by selling support and updates on their software.
But when you want to use RHEL but you don’t want to have to create an account on RHN and pay for it, you mostly can’t update your system. So you quickly have an operating system out of date with unpatched security holes. Anyway, I hope only few people like me try to use RHEL without a subscription.
An alternative is to use CentOS, which is mostly the same as RHEL but closer to the open source mindset.
Anyway, good people use Debian (stable or testing branches) .