Discuss February 2016

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126 participants
101 discussions

Strange performance issue on CentOS 6.7 server
by Alfred von Campe 05 Feb '16

05 Feb '16

I’m running CentOS 6.7 on my build servers, and on one of the servers the builds are taking almost an order of magnitude longer than usual. There are no runaway processes and there is plenty of free memory. So I suspected that file I/O might be slow, and sure enough, that appears to be the case. I ran a simple dd test and compared the results to a “normal” build server (412 MB/s vs. 31.7 MB/s). Both are on similarly configured VGs on identical hardware. What could cause this performance degradation and are there any other tests I can run before I reboot the server to see if things improve? There is nothing in /var/log messages - are there other logs I should check? Alfred

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devtoolset-4
by Kay Diederichs 05 Feb '16

05 Feb '16

Hi, is there any way to get access to devtoolset-4 ? I see alot of stuff at http://cbs.centos.org/koji/packageinfo?packageID=2076 . Is this not yet released? thanks, Kay

2 1

delete directories with find and exclude other directories
by Tim Dunphy 04 Feb '16

04 Feb '16

Hi all, I'm attempting to delete some directories and I want to be able to exclude a directory called 'logs' from being deleted. This is my basic find operation (without the exclusion) # find . -type d |tail -10 ./d20160124-1120-df8mfb/deployments ./d20160124-1120-df8mfb/releases ./d20160131-16993-vazqg5 ./d20160131-16993-vazqg5/metadata ./d20160131-16993-vazqg5/deployments ./d20160131-16993-vazqg5/releases ./logs ./d20160203-27735-1tqbjh6 ./d20160125-1120-1yccr9p ./d20160131-16993-1yf9lnc I'm just tailing the output so that you have an idea of what's going on without taking up the whole page. :) If I try to exlclude the logs directory with the prune command I get back no results. root@ops-manager:/tmp/tmp# find . -type d -prune -o -name 'logs' -print root@ops-manager:/tmp# What am I doing wrong? Thanks, Tim -- GPG me!! gpg --keyserver pool.sks-keyservers.net --recv-keys F186197B

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CentOS 7 regression, can not take a KVM qcow2, convert it and boot it on ESXi...
by Martinx - ジェームズ 04 Feb '16

04 Feb '16

Guys, I have a Packer build procedure, that works like a charm, when with CentOS 6.7. Exemplifying: 1- Packer (with virtio disk) + QEmu + CentOS 6.7 ISO; 2- Create a RAW image; 3- Convert the RAW image into QCOW2 for KVM hypervisors (okay); 4- Convert the RAW image into VMDK for ESXi hypervisors (okay). However, when doing the very same procedure, with CentOS 7.2 ISO, it does not boot on ESXi! After research, I realized that it is not auto-loading the sd_mod on ESXi. I'm seeing errors like this: dracut-initqueue timeout dracut-initqueue timeout .... And it drops to "dracut#" shell, where I can see that there is no /dev/sda listed on /proc/partitions. I think I tried everything! My last try was, during Packer build, to append "add_drivers+=" sd_mod" to /etc/dracut.conf and re-building initramdisk by running "dracut -f". However, it does not boot either (on ESXi)! I can still boot using Rescue mode on VMWare, then, I can see that sd_mod is inside of initramfs as expected (lsinitrd FTW) but, dracut does not load it! I tried "force_drivers+=" sd_mod", doesn't work too... Weird is that, while during Rescue, if I run "dracut -f" again, then, it works! Normal boot proceeds... But this is unacceptable, because I can not ship a half-broken VMDK and tell customers to first boot on Rescue, run "dracut -f" and then, use the system. So, why the heck the "dracut -f" executed when as a KVM guest have no effect for later ESXi usage? What am I missing? I really appreciate any help! Thanks! Thiago

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Re: [CentOS] CentOS 7, NSF, "feature" [SOLVED]
by m.roth＠5-cent.us 04 Feb '16

04 Feb '16

The issue: NFS fails to start in CentOS 7 if it cannot resolve any of a list of hosts. Well, my manager had to google to find the *truly* obscure solution that uses a deeply oddball syntax. In /usr/lib/systemd/system/nfs-server.service, you edit the following line so that it looks like this: ExecStartPre=-/usr/sbin/exportfs -r Notice the *deeply* weird syntax of "=-<cmd>". This apparently tells it that "a nonzero exit code" should be ignored and considered "success". And, I read in the manpage for systemd.service that if you precede it with an @, it will pass arguments. Why it does not use the used-everywhere-else of *post*fixing those parms, I have no data. And, speaking specifically about nfs-server.service, I also don't understand why you'd set as an out-of-the-box default that it should fail to come up if it can't resolve any export host, rather than default to coming up. mark, discovering new reasons to dislike systemd

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I am not understanding the size of the iso
by Ramaseshan S 04 Feb '16

04 Feb '16

I suppose, CentOS 7 ships with DVD and minimal version. While the minimal version is just 700M, what makes the minimal along with a GUI about 4.3 GB. Isint it too huge for an OS ? -- Cheers -- S.Ramaseshan Engineer fractalio.com ramaseshan(a)fractalio.com

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CentOS 7, NSF, "feature"
by m.roth＠5-cent.us 03 Feb '16

03 Feb '16

In the last month, we've discovered a new, ahhhh, "feature" in the version of the version of NFS with CentOS 7: on startup, if it cannot resolve a given host, it dies. It does not continue on up, with all the other hosts it's exporting to, and just log a message. Is there a workaround, or a configuration, to change this "fail on unresolved host" behaviour? mark

4 5

nfs stuck, don't know what processes to kill
by Dave Burns 03 Feb '16

03 Feb '16

My NFS server is up and other clients can access x. One particular client can't. I tried to unmount the NFS share: [root@nfsclient ~]# umount -f /disk/x umount2: Device or resource busy umount.nfs: /disk/x: device is busy umount2: Device or resource busy umount.nfs: /disk/x: device is busy If I use df or lsof to try to figure out what process to kill, they hang. I am reluctant to just reboot, as many other users are getting stuff done. dmesg doesn't show anything useful. How to get unstuck? thanks, Dave

4 6

hot do use iscsi loopback
by lejeczek 03 Feb '16

03 Feb '16

hi everybody I've looked it up on the net but info is scarce. Could please someone explain how to use loopback and what is purpose? many thanks

1 1

Re: [CentOS] Latest version of kate editor
by James B. Byrne 03 Feb '16

03 Feb '16

On Tue, February 2, 2016 12:02, H wrote: > > What do people use as a programming editor on CentOS 6? My first > impression of kate was favorable, not only did it support the usual > programming and scripting languages but also markdown which I have > recently discovered... > > I use vim/gvim together with numerous add-ons from Tim Pope. -- *** e-Mail is NOT a SECURE channel *** Do NOT transmit sensitive data via e-Mail James B. Byrne mailto:ByrneJB@Harte-Lyne.ca Harte & Lyne Limited http://www.harte-lyne.ca 9 Brockley Drive vox: +1 905 561 1241 Hamilton, Ontario fax: +1 905 561 0757 Canada L8E 3C3

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Discuss February 2016