Discuss

discuss@lists.centos.org

34753 discussions

Retrieving POP mail from server to server
by Jussi Hirvi 13 Aug '10

13 Aug '10

I need to transfer a client's email inbox from another mail server to our mail server (Centos 5). This is needed once only (or maybe a couple of times). What is the best command-line tool? Fetchmail? I did this once before, with another tool, but have forgotten. - Jussi -- Jussi Hirvi * Green Spot Topeliuksenkatu 15 C * 00250 Helsinki * Finland Tel. +358 9 493 981 * Mobile +358 40 771 2098 (only sms) jussi.hirvi(a)greenspot.fi * http://www.greenspot.fi

6 5

DHCP problem with virtual interfaces
by Simone Caldana 13 Aug '10

13 Aug '10

Hello, After asking around in #centos and other linux related IRC channels, here I am, bugging all of you. brace for the long post. (tldr: dhclient loses virtual interface ips) I set up a system to deploy statically assigned IPs to physical and virtual interfaces to a number of (virtual) machines. I have a DHCPD with an entry for each virtual ip in the form of host eth0-1.virt1.test.it { option dhcp-client-identifier "00:50:56:00:84:00-eth0:1"; fixed-address 10.192.52.132; } where 00:50:56:00:84:00 is the physical mac address, but that's irrelevant. on the client machine I got inside sysconfig's system and wrote a custom ifup-local-eth0 that launches one dhclient per virtual interface, like: /sbin/dhclient -1 -q -lf /var/lib/dhclient/dhclient-eth0:1.leases -pf /var/run/dhclient-eth0:1.pid eth0:1 always on the client in dhclient.conf I have entries like: interface "eth0:1" { send dhcp-client-identifier "00:50:56:00:84:00-eth0:1" ; } at service network start everyone is happy, virtual interfaces gets configured and everything works. after a while (hours, days) suddenly _some_ (not alway all of them, sometimes 1 out of 10, sometimes 9 out of 10) of the virtual IPs disappear. in the DHCPD log files I see things like (not the same machine, because on that I didn't have the issue recently): Aug 11 16:39:52 cp1 dhcpd: DHCPREQUEST for 10.192.52.103 from 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPACK on 10.192.52.103 to 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPREQUEST for 10.192.52.103 from 00:50:56:00:37:00 via eth1: lease 10.192.52.103 unavailable. Aug 11 16:39:52 cp1 dhcpd: DHCPNAK on 10.192.52.103 to 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPDISCOVER from 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPOFFER on 10.192.52.102 to 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPREQUEST for 10.192.52.102 (10.192.50.21) from 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPACK on 10.192.52.102 to 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPDISCOVER from 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPOFFER on 10.192.52.103 to 00:50:56:00:37:00 via eth1 Aug 11 16:39:52 cp1 dhcpd: DHCPREQUEST for 10.192.52.102 (10.192.50.21) from 00:50:56:00:37:00 via eth1: lease 10.192.52.102 unavailable. Aug 11 16:39:52 cp1 dhcpd: DHCPNAK on 10.192.52.102 to 00:50:56:00:37:00 via eth1 Also, in the clients' leases file I find leases for ips that should go to othe dhclients on the same machine. My guesses are either: a) dhclient doesn't always send dhcp-client-identifier and thus the server can't verify the IP they claim is theirs. why this doesn't happens at every renew I don't know (I tried using very short lease times, and wasn't able to reproduce the issue). b) dhclients steals DHCPOFFER replies from each other, leading the stealing DHCP take charge of the stolen from IP and having its original one fade into oblivion. to work around b) I tried to point the N dhclients to the same lease file, but this still lead to NAKs (albeit not lost IPs) _and_ a strangely looking leases file, with empty lines but apparently no significant corruption. software versions: # dhcpd -V Internet Systems Consortium DHCP Server V3.0.5-RedHat # dhclient -V Internet Systems Consortium DHCP Client V3.0.5-RedHat the problem happened also using DHCP Server 3.0.1 on an older CentOS 4.5 I'm looking for ideas to better pinpoint the problem, alternatives, anything. possible FAQs: Q) do you have dynamic ip pools on the DHCP server? A) yes, but not on this subnet. This subnet only has statically assigned ips, both physical (mapped with MAC addresses) and virtual (mapped with dhcp-client-id Q) do you see IPs assigned on the wrong machine? A) never happened. Q) do service network restart fix the issue? A) yes, always, and yes, temporarily. This makes me think the system is basically right and this may be a bug. Q) do you have network issues? A) no, and this doesn't seem to happen in moments where a network related problem may be likely Q) why don't you use sysconfig virtual interfaces configuration files? A) they doesn't support DHCP, only static IPs Q) did you try building a newer dhclient/dhcpd? A) I built 4.2's dhclient from ISC sources but the pair dhclient/dhclient-script isn't a drop in replacement for CentOS. Q) why don't you use static IPs, if they are static in DHCP? A) I want to be able to reconfigure the networks without editing tons of files on tons of machines. I currently have tens of these VMs deployed and the number is likely to increase alot in the future. The deployment and configuration is automatic using a central configuration. Attached a txt with the tcpdump of the above log extraction. Thanks. -- Simone Caldana Senior Consultant Critical Path via Cuniberti 58, 10100 Torino, Italia +39 011 4513811 (Direct) +39 011 4513825 (Fax) simone.caldana(a)criticalpath.net http://www.cp.net/ Critical Path A global leader in digital communications

2 4

tar - ssh - standard out
by Tom Brown 13 Aug '10

13 Aug '10

Hi I have a process that creates 'some data' and outputs this to standard out and i want to shift this data over ssh to a remote box without ever writing anything locally. I have been experimenting with tar to create the archive as the i dont know what the contents of 'some data' might be so i just need to capture it and output it on the other side. I have been trying with $ tar czf - . | ssh -q 192.168.122.2 "tar xzf -" and this works fine to create an archive of this '.' directory and pipe that over to the other side but i want to take standard out so.... $ tar czf - `the thing that generates standard out here` | ssh -q 192.168.122.2 "tar xzf -" Would that work or is there a better way to get this over to the other side? It needs to be a data stream though so things like scp and rsync are no good and i need to know what the command is on the remote side being run so that i can restrict this in the ssh public key on the remote side. thanks

8 11

Problem resizing partition of nfs volume
by Dan Yamins 13 Aug '10

13 Aug '10

Hi: I have an NFS volume that I'm trying to resize a partition on. Something about the fdisk process is corrupting something on the drive Before running fdisk, I can mount the volume find: $ mount /dev/sdo1 /home ... and the volume is mounted fine. And, $ e2fsck -f /dev/sdo1 /dev/sdo1: clean, ... But then I run fdisk to rewrite the partition table of this drive, to expand the /dev/sdo1 partition w/o losing data: $ fdisk /dev/sdo # Type 'd' to delete the primary partition # Type 'n' for new partition # Type 'p' for primary # Type '1' for 1st # Type Enter for 1st cylinder # Type Enter for last cylinder (full disk) # Type 'w' to finish Calling ioctl() ... Syncing disks ... But then something has gone wrong. $ e2fsck -f /dev/sdo1 e2fsck 1.39 (29-May-2006) Couldn't find ext2 superblock, trying backup blocks... e2fsck: Bad magic number in super-block while trying to open /dev/sdm1 ... And I can't mount the volume any more: $ mount /dev/sdo1 /home mount: you must specify the filesystem type What am I doing wrong? Am I missing a step of the process? Thanks! Dan

4 7

Ext3 undelete
by Jason Pyeron 12 Aug '10

12 Aug '10

I was fooled by a hard link trying to clean up disk space. How can I undelete many files? (time is of the essence as I cannot unmount the partition) -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- - - - Jason Pyeron PD Inc. http://www.pdinc.us - - Principal Consultant 10 West 24th Street #100 - - +1 (443) 269-1555 x333 Baltimore, Maryland 21218 - - - -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- This message is copyright PD Inc, subject to license 20080407P00.

3 5

xen vs kvm for virtualization on centos/rhel?
by Robert P. J. Day 12 Aug '10

12 Aug '10

as i'm reviewing the courseware for the rhel (centos) course i'm teaching next week, i'm going to ask the occasional question, possibly technical, possibly more policy. first one involves the choice for virtualization. the course has a short section involving virt using xen but everything i've read suggests that red hat is concentrating on kvm for virt. thoughts on that? i have the freedom to replace the xen section with one covering kvm instead. rday -- ======================================================================== Robert P. J. Day Waterloo, Ontario, CANADA Top-notch, inexpensive online Linux/OSS/kernel courses http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

10 16

NTFS is more resilient than ext3? Or is it hardware issue?
by Fajar Priyanto 12 Aug '10

12 Aug '10

Hi guys, I don't mean to incite debate or something, just want to share experience and a little curiosity. Back long time ago, we have an old file MS W2K (NTFS) server where due no admin was available to manage it, the server would get power off when the office closed, and auto power on again in the morning. That thing happened for years and it was fine ^^ Recently, I setup a Centos 5.5 file server with ext3 and got power blackout twice and I notice the filesystem got corrupted and also bad sectors. Is it just pure random luck, software or hardware issue? What's your experience? Thank you.

8 7

problems with yum_priorities on CentOS5/RHEL5
by Nick 12 Aug '10

12 Aug '10

Hello, Many of you will have read this page, with its (somewhat ambiguous) endorsement of yum_priorities: http://wiki.centos.org/AdditionalResources/Repositories/RPMForge As I gather has been stated before on the centos list [1], that quote stops short of outlining what exactly is wrong with yum_priorities (YP) and why it's the best solution. In fact it goes on to say: > as of yet, no real world problems have been reported with regard to the > 'yum-priorities' plugin Some (I hope, constructive) comments which might help users of yum/YP to avoid surprises: - The above statement should be altered, since it obviously isn't true (Judging both from comments in [1] and my own experience in [2]) - Perhaps it could explain how YP works and when it doesn't with an example? (I have one you are welcome to copy in [2].) - Could the above page incorporate, or at least link to the useful information at the bottom of the page here: http://wiki.centos.org/PackageManagement/Yum/Priorities - Could it also mention somewhere quite visible that yum_priorities is not available on RHEL5 so any solutions using YP it will just not work there? I'd also like to know more about why YP cannot be made available on RHEL, but I guess this is not the place to ask. Plus I've noticed a couple of features of yum + YP which aggravate the shortcomings - again this is probably not the place, but I'll mention them anyway, as a heads-up to other users. 1. yum check-updates and yum update do *not* warn you of an impending unresolved dependency caused by YP hiding the required package. It seems the only way to find out is if you go ahead and try and perform the update, which potentially leaves you with one or more broken packages. This seems a serious flaw that should be fixed. 2. Not only do higher priority packages totally eclipse lower priorities, whatever version, but yum_priorities also makes it seem like they aren't even present. When a dependency is eclipsed, yum queries with --showduplicates will tell you there *is* no package which satisfies the missing requirement, making it look like the repository is broken. You have to disable all plugins to get the correct answer: $ yum --showduplicates --noplugins list perl-Archive-Tar Finally, I'd like to ask if there have been any developments, or new advice anyone can offer on the topic, since November 2009? Thanks, Nick 1. http://thread.gmane.org/gmane.linux.centos.general/86563 2. An example of when yum_priorities bites included here: http://www.noodlefactory.co.uk/~nick/wu-lee/Notes/YumPrioritiesPitfalls Comments welcomed.

2 3

OpenOffice.org 3.1.1 Calc autofill does not work
by Nicholas 12 Aug '10

12 Aug '10

Hi all, Has anyone upgraded OpenOffice.org 3.1.1 on Centos 5.3? Everything seemed fine but I have found 1 problem on Calc. The autofill does not work. Example, when I type "Jan" in cell A5 and drag the handle to cell D5, the Fill Settings dialog box pops up instead of the Feb, Mar, Apr filling in the cell automatically. When OpenOffice.org 3.1.1 from Sun is installed, it works. Is there some setting in CentOS that needs to be done? -- Nicholas AS -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.

2 1

manage (iscsi storage) LVM
by Götz Reinicke - IT-Koordinator 11 Aug '10

11 Aug '10

Hi, it is possible to create and setup/format volumes on a iscsi storage on one server and than disconnect and attache the storage to an other server. AFAIK on the 'new' server I do have to launch an LVM-scan command ... after login to the iscsi target. But which LVM-command and syntax was it? Thanks for any hint! :) /Götz -- Götz Reinicke IT-Koordinator Tel. +49 7141 969 420 Fax +49 7141 969 55 420 E-Mail goetz.reinicke(a)filmakademie.de Filmakademie Baden-Württemberg GmbH Akademiehof 10 71638 Ludwigsburg www.filmakademie.de Eintragung Amtsgericht Stuttgart HRB 205016 Vorsitzende des Aufsichtsrats: Prof. Dr. Claudia Hübner Geschäftsführer: Prof. Thomas Schadt

2 2

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Discuss