Discuss December 2008

discuss@lists.centos.org

247 participants
257 discussions

does anyone have experience with clusters?
by Rudi Ahlers 04 Dec '08

04 Dec '08

Hi all, I want to start experimenting with clusters, and I would like to use normal desktop grade hardware for this. I have some extra PC components lying around, enough to build 3 - 4 moderate desktops with a PIV / C2D CPU & 512MB - 1GB RAM each. All the machines should have at least a 100MB NIC, but I can add a gigabit NIC to the machines that doesn't have it if need be. I have used Linux Heartbeat to failover a MySQL cluster before, and it's actually been running very well for about 3 years now. But, I want to start looking @ total clustering, with DRBD - where everything (not just MySQL) is being replicated across the 4 machines. I'm also intereated in load balancing. Has anyone done anything like this? The cluster will be running / hosting a few XEN Virtual Machines, and idealy if one PC / server dies (hardware failure / power failure / etc), then on of the other machines should still be running the virtual machines, i.e. no downtime. Is this possible? Can somone steer me into a direction where I can get more info on this? My aim: to use common, cheap PC equipment & CentOS for the project, I don't want to spend any more money, and want to use what I have. -- Kind Regards Rudi Ahlers

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Sound problem in Dell inspiron 1525
by Ern jura 03 Dec '08

03 Dec '08

After installing CentOS 5.2 on my Dell inspiron 1525 laptop, the sound was inactive, I then installed Alsa-Driver, Alsa-utils, Alsa-plugins and Alsa-libs the ATrpms site. The speakers then work fine, but when I plug in headphones, the sound begins to fade out and eventually becomes completely quiet. I have checked the Volume Manager and nothing is muted including the Headphones volume, when I unplug the headphones the speakers are also quiet. The sound card is a HDA-INTEL. Any suggestions and solutions? NOTE: THE SPEAKERS WORK FINE, THE PROBLEM ONLY OCCURS THE MOMENT I PLUG IN HEADPHONES. HOW CAN I USE HEADPHONES?

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User access to /dev/ttyUSB0
by Frank Cox 03 Dec '08

03 Dec '08

I have been trying to get an EVDO modem to work with Centos 5. I can make it dial out with wvdial only when I'm the root user. Otherwise I get this error: Cannot open /dev/ttyUSB0: Device or resource busy I added the user to the uucp group. crw-rw---- 1 root uucp 188, 0 Dec 3 02:30 /dev/ttyUSB0 crw-rw---- 1 root uucp 188, 1 Dec 3 02:30 /dev/ttyUSB1 crw-rw---- 1 root uucp 188, 2 Dec 3 02:30 /dev/ttyUSB2 crw-rw---- 1 root uucp 188, 3 Dec 3 02:30 /dev/ttyUSB3 What have I missed? -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com DRY CLEANER BUSINESS FOR SALE ~ http://www.canadadrycleanerforsale.com

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Yum upgrade inside firewall
by mcclnx mcc 03 Dec '08

03 Dec '08

We have several CENTOS 4.X which inside Firewall. I can NOT run "yum" inside firewall to upgrade O.S. to new release. Does there has way I can download all RPM to otherside firewall server then transfer those files into servers inside firewall and upgrade. Anyone have procedure dicuments or website can be reference? Thanks. ______________________________________________________________________________________________________ 付費才容量無上限？Yahoo!奇摩電子信箱2.0免費給你，信件永遠不必刪！ http://tw.mg0.mail.yahoo.com/dc/landing

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system-config-network crash
by Frank Cox 03 Dec '08

03 Dec '08

I have been trying to get a EVDO modem to work with Centos 5 and earlier this evening I used system-config-network to add it to the system. Now when I try to run system-config-network again it crashes with the following error. Can anyone tell me how I can fix this? Component: system-config-network Version: 1.3.99.10 Summary: TBa9c752cb ConfPAP.py:85:initvars:IndexError: list index out of range Traceback (most recent call last): File "/usr/sbin/system-config-network-gui", line 167, in main window = mainDialog() File "/usr/share/system-config-network/netconfpkg/gui/maindialog.py", line 247, in __init__ self.load() File "/usr/share/system-config-network/netconfpkg/gui/maindialog.py", line 270, in load self.loadDevices() File "/usr/share/system-config-network/netconfpkg/gui/maindialog.py", line 278, in loadDevices devicelist = getDeviceList() File "/usr/share/system-config-network/netconfpkg/NCDeviceList.py", line 301, in getDeviceList __DVList.load() File "/usr/share/system-config-network/netconfpkg/NCDeviceList.py", line 84, in load newdev.load(dev) File "/usr/share/system-config-network/netconfpkg/plugins/NCDevModem.py", line 36, in load self.Dialup.load(conf) File "/usr/share/system-config-network/netconfpkg/NCDialup.py", line 513, in load Dialup.load(self, parentConf) File "/usr/share/system-config-network/netconfpkg/NCDialup.py", line 128, in load papconf = getPAPConf() File "/usr/share/system-config-network/netconfpkg/NC_functions.py", line 288, in getPAPConf DVpapconf = ConfPAP.ConfPAP(netconfpkg.ROOT + PAPFILE) File "/usr/lib/python2.4/site-packages/rhpl/ConfPAP.py", line 32, in __init__ Conf.Conf.__init__(self, filename, '#', ' \t', ' \t') File "/usr/lib/python2.4/site-packages/rhpl/Conf.py", line 180, in __init__ self.read() File "/usr/lib/python2.4/site-packages/rhpl/ConfPAP.py", line 37, in read self.initvars() File "/usr/lib/python2.4/site-packages/rhpl/ConfPAP.py", line 85, in initvars self.vars[var[0]][var[1]] = var[2] IndexError: list index out of range Local variables in innermost frame: var: [''] self: <rhpl.ConfPAP.ConfPAP instance at 0xb7a3360c> -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com DRY CLEANER BUSINESS FOR SALE ~ http://www.canadadrycleanerforsale.com

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how to rescan serial ports without reboot
by Rudi Ahlers 03 Dec '08

03 Dec '08

Hi all, I hope this is possible. I have a server, with a network switch attached to the serial port, and I want to rescan the serial port (/dev/tty) to see if it picks it up? I'd prefer not to reboot the server if at all possible. dmesg reports ttyS0 as the active port: [root@zabackup01 ~]# dmesg |grep tty Bootdata ok (command line is ro root=/dev/System/root rhgb quiet xencons=tty6) Kernel command line: ro root=/dev/System/root rhgb quiet xencons=tty6 WARNING: Failed to register Xen virtual console driver as 'tty1' serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A ttyS0: 1 input overrun(s) ttyS0: 1 input overrun(s) running screen /dev/ttyS0 doesn't show up anything, and I should at least get the switch's login prompt. -- Kind Regards Rudi Ahlers

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Strange UserID Issue
by Mohan 03 Dec '08

03 Dec '08

Hi Guys, I have a setup where i have a user named root4 whose uid and gid are set to 0 so that it behaves as root user. The root user has ssh keys configured to access other servers . In the existing setup all other servers with similar setup shows whoami as root ,though i login with the username root4. In one of the servers all of a sudden it shows as root4 instead of root. The only change i did a day ago was installed fluxbox and k3b for burning dvd-backups in the server itself. Since it shows whoami as root4. ssh checks /home/root4/.ssh for ssh keys instead of checking in /root/.ssh/ so i have to copy all the keys manually from default location to /home/root4/.ssh to get the ssh key based authentication working . This machine runs centos 4.5 Id still shows uid =0 (root4) gid=0(root) groups=0(root) but its supposed to show uid =0 (root) gid=0(root) groups=0(root) Earlier all files in /home/root4 are owned by user and group root.root now it shows root4. root. i checked the passwd file last modification date and it hasnt been changed for months. root4:x:0:0::/home/root4/:/bin/bash selinux is disabled $HOME=/home/root4 -- which is normal. I dont know why it behaves all of a sudden. does anyone have experienced similar problem ? Where should i look for to fix this issue ? Any help would be much appreciated. -- Regards, Mohan.

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mysql question
by ann kok 03 Dec '08

03 Dec '08

Hi All Can I know what is the meaning of the position? Why there is nothing in the "Binlog_Ignore_DB" mysql> show master status; +-------------------+----------+---------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +-------------------+----------+---------------+------------------+ | mysqld-bin.000006 | 183219 | dbname,dbname | | +-------------------+----------+---------------+------------------+ Thank you __________________________________________________________________ Instant Messaging, free SMS, sharing photos and more... Try the new Yahoo! Canada Messenger at http://ca.beta.messenger.yahoo.com/

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Xen-Version in CentOS 5.3?
by Dirk H. Schulz 03 Dec '08

03 Dec '08

Hi folks, I tried to find out what xen version upstream intends to use in 5.3, but did not find anything. So now I hope that there is some secret knowledge among the CentOS people you could share? :-) Any hint or link would be helpful. Thanks in advance, Dirk

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CentOS-4 Xen kernel with low RAM and Badness in local_bh_enable at kernel/softirq.c:141
by Kingsly John 03 Dec '08

03 Dec '08

I have small xen VM running centos4 which acts as a router/firewall, and has been working fine for over 1.5 years with 32MB of RAM and a kernel I either got from xensource.org or built myself from their sources. (centos 4 didn't have a xen kernel back then) I lost the kernel to a corrupted disk and decided to use the centos provided xen kernel. All these months 32MB + 64MB Swap was more than sufficient and I never had any problems.(3-digit uptimes) The CentOS Xen kernel is unusable at 32MB and invokes the OOM killer even though there is plenty of swap free (and about 5-10MB of RAM too). After the OOM killer has done it's job there's about 15 MB of RAM free and swap is hardly used at all (1MB at most) I've increased RAM to 64MB and the OOM killer doesn't kick in.. but I am seeing plenty of such messages in the logs ... Dec 2 16:05:21 noc kernel: Badness in local_bh_enable at kernel/softirq.c:141 Dec 2 16:05:21 noc kernel: [<c0121178>] local_bh_enable+0x47/0x6f Dec 2 16:05:21 noc kernel: [<c02177d5>] skb_checksum+0x133/0x25e Dec 2 16:05:21 noc kernel: [<c0250f06>] udp_poll+0x66/0x113 Dec 2 16:05:21 noc kernel: [<c02135fd>] sock_poll+0x19/0x1d Dec 2 16:05:21 noc kernel: [<c016d1a6>] do_select+0x190/0x2c7 Dec 2 16:05:21 noc kernel: [<c016ceb5>] __pollwait+0x0/0x9b Dec 2 16:05:21 noc kernel: [<c0144ae4>] __kmalloc+0x56/0xd3 Dec 2 16:05:21 noc kernel: [<c016d5dc>] sys_select+0x2e7/0x45c Dec 2 16:05:21 noc kernel: [<c010740f>] syscall_call+0x7/0xb Any idea what's causing it / how to make it stop ? I'm running Centos 5 in Dom0 and CentOS 4 in the router domU and there's another couple of Centos 5 domU which are running error free. Kingsly -- --------------------------------------------------------------------------- Kingsly At Users Dot SourceForge Dot Net -- http://kingsly.org/ ---------------------------------------------------------------------------

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Discuss December 2008