Discuss July 2010

discuss@lists.centos.org

242 participants
194 discussions

why i can not put my swap files in /dev?
by Tang Jianwei 06 Jul '10

06 Jul '10

I tried to create some swap files in /dev directory for my desktop. the dd and mkswap were ok. but when I try to swapon it, i get this: # swapon /dev/myswap swapon: /dev/myswap: Invalid argument but when I mv the file to some other directory like /mnt or /, the swapon works. could sb. tell me why? -- Tang Jianwei

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CentOS Cluster
by Torintino T 06 Jul '10

06 Jul '10

Dear All, I am newbie to Linux Clustering, i have 2 standalone CentOS servers, i want to setup a cluster on those servers, to synchronize between each other, and to make a one as standby to the other, if a one fails the other will switchover. I will mostly use Apache, Mysql, and PHP. I have read the "Cluster Administration" document, i found that there are multiple methods to setup the cluster, actually i want to ask expert people in the clustering, which method is the most proper one, and should i have use a fence device, which one i will preferably use. Thanks for assistance. _________________________________________________________________ Hotmail: Powerful Free email with security by Microsoft. https://signup.live.com/signup.aspx?id=60969

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setuproot: moving /dev/failed:No such file or directory
by Bernard Lheureux 06 Jul '10

06 Jul '10

Since my upgrade of the CentOS 5.4 to 5.5, it is impossible to boot from kernel 2.6.18-194.xx but older kernel (2.6.18-164-xx) boots perfectly The message I get is: setuproot: moving /dev/failed:No such file or directory* *And I get a Kernel Panic... It seems like the system was unable to mount /dev in ram, then it cannot find it... How is it possible and how to solve this ?* *-- (°- Bernard Lheureux Gestionnaire des MailingLists ML, TechML, LinuxML //\ http://www.bbsoft4.org/Mailinglists.htm ** MailTo:root@bbsoft4.org v_/_ http://www.bbsoft4.org/<<<<<< *>>>>>> http://www.portalinux.org/ ------------------------------------------------------------------------

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DRBD update
by Daniel Bruno 05 Jul '10

05 Jul '10

Hello, Someone had some problem recently with DRBD updates? Thanks, -- Daniel Bruno http://danielbruno.eti.br

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Limiting fuse-mounted NTFS drive access?
by Scott Ehrlich 05 Jul '10

05 Jul '10

I have a CentOS 5.5 system that is dual-boot CentOS 5.5 and Windows XP w/SP3 formatted with NTFS (for the Windows partition, of course). I have installed fuse (ntfs-3g) to allow read/write access to the NTFS partition from CentOS. No regular user has sudo. What is the best way to limit the access a user logging into the CentOS from mangling or changing data in unwanted areas of the fuse-mounted NTFS partition? I presume this would be somewhere in /etc/fstab, but what should the mount line say for at least write limitations? Thanks. Scott

2 1

centos 5.2
by Roland RoLaNd 05 Jul '10

05 Jul '10

Hello, where can i get centos 5.2 64 bit ? all i can find is 5.5 ... any help? _________________________________________________________________ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. https://signup.live.com/signup.aspx?id=60969

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text to html
by Jozsi Avadkan 05 Jul '10

05 Jul '10

input: http://pastebin.com/raw.php?i=MqPXZwc3 output: http://pastebin.com/raw.php?i=8QCkp4yv it will be a long day.. :D could someone please help with it? i have to make a "one liner" that get's the input, and gives the mentioned output.

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prelink
by Frank Cox 05 Jul '10

05 Jul '10

The above discussion of prelink gave me pause for thought... I have a "suite" of programs that I install in their own directory, along with their datafiles, under /opt. Would it be a good idea to add that directory to /etc/prelink.conf? What could go wrong? -- MELVILLE THEATRE ~ Melville Sask ~ http://www.melvilletheatre.com

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qemu
by mattias jonsson 05 Jul '10

05 Jul '10

How to use qemu with a network brdige The bridge should have dhcp Not nat

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ESXi, KVM or Xen?
by Emmanuel Noobadmin 03 Jul '10

03 Jul '10

Which of these would be the recommended virtualization platform for mainly CentOS guest on CentOS host for running a virtualized mail server? From what I've read, objectively it seems that VMWare's still the way to go although I would had like to go with Xen or KVM just as a matter of subjective preference. VMWare's offering seems to have the best support and tools, plus likely the most matured of the options. Also given their market dominance, unlikely to just up and die in the near future. Xen would had been a possible option except Redhat appears to be focusing on KVM as their virtualization platform of choice to compete with VMWare and Citrix. So maybe Xen support will be killed shortly. Plus the modified xen kernel apparently causes conflict with certain software, at least based on previous incidents where I'd been advised not to use the CentOS xen kernel if not using xen virtualization. KVM would be ideal since it's opensource and would be supported in CentOS as far as can be reasonably foreseen. However, looking at available resources, it seems to have these key disadvantages 1. Poorer performance under load. http://wiki.xensource.com/xenwiki/Open_Topics_For_Discussion?action=AttachF… This 2008 XenSummit paper indicates that it dies on heavy network load as well as when there are more than a few VM doing heavy processing at the same time. But that's two years ago and they weren't using paravirtual drivers it seems. http://vmstudy.blogspot.com/2010/04/network-performance-test-xenkvm-vt-d.ht… This blog testing out Xen/KVM pretty recently. While the loads are not as drastic and neither the difference, it still shows that KVM does lag behind by about 10%. This is a concern since I plan to put storage on the network and the most heavy load the client has is basically the email server due to the volume plus inline antivirus and anti-spam scanning to be done on those emails. Admittedly, they won't be seeing as much emails as say a webhost but most of their emails come with relatively large attachments. 2. Security Some sites point out that KVM VM runs in userspace as threads. So a compromised guest OS would then give intruder access to the system as well as other VMs. Should I really be concerned or are these worries only for extreme situations and that KVM is viable for normal production situations? Are there other things I should be aware of?

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Discuss July 2010