Discuss October 2014

discuss@lists.centos.org

199 participants
220 discussions

Centos 7: Remove Gnome from GDM options
by Frank Cox 06 Oct '14

06 Oct '14

When you click on the gear icon on the GDM login screen, it provides a list of the available desktop environments so you can pick between them. Since I exclusively use Mate on this computer, how can I remove the other options from that menu? Earlier today when I logged in the machine decided on its own that what I really wanted was Gnome Classic, so I had to log out to change it back to Mate, then log in again. I would like to tell it to use Mate exclusively, with no other options to select by mistake. -- MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com

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lvcreate error
by Aaron Siegel 06 Oct '14

06 Oct '14

Hello I am unable create a new logical volume, I receive the following error when using lvcreate # lvcreate -L 1g -n system3_root hm device-mapper: resume ioctl on failed: Invalid argument Unable to resume hm-system3_root (253:7) Failed to activate new LV. # pvs PV VG Fmt Attr PSize PFree /dev/sda4 hm lvm2 a-- 998.00g 864.75g # gvs VG #PV #LV #SN Attr VSize VFree hm 1 6 0 wz--n- 998.00g 864.75g #lvs LV VG Attr LSize Pool Origin Data% Move Log Cpy% Sync Convert docker hm -wi-ao---- 15.00g libvirt-images hm -wi-ao---- 63.24g swap0 hm -wi-ao---- 30.00g system2_root hm -wi-ao---- 15.00g system2_var hm -wi-ao---- 5.00g system3_var hm -wi-a----- 5.00g

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CentOS 7 - Have 2 disks, each with a biosboot partition, can only boot off one of them
by Digimer 05 Oct '14

05 Oct '14

Hi all, I used a kickstart script to setup a new machine of mine with RAID 1 (I couldn't get anaconda to create matching partition schemes). So I've now got /dev/sdg1 and /dev/sdh1 as 'bios_grub' (/dev/sd{a-f} are a separate array). 0 root@an-nas02:~# parted /dev/sdg print free Model: ATA ST3000NC000 (scsi) Disk /dev/sdg: 3001GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Disk Flags: pmbr_boot Number Start End Size File system Name Flags 17.4kB 1049kB 1031kB Free Space 1 1049kB 3146kB 2097kB bios_grub 2 3146kB 3001GB 3001GB raid 3001GB 3001GB 466kB Free Space 0 root@an-nas02:~# parted /dev/sdh print free Model: ATA ST3000NC000 (scsi) Disk /dev/sdh: 3001GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Disk Flags: pmbr_boot Number Start End Size File system Name Flags 17.4kB 1049kB 1031kB Free Space 1 1049kB 3146kB 2097kB bios_grub 2 3146kB 3001GB 3001GB raid 3001GB 3001GB 466kB Free Space I can only boot off of /dev/sdh, so I tried to run 'grub2-install' against /dev/sdg and it failed with this error: *** Error in `grub2-install': double free or corruption (fasttop): 0x00000000010a83b0 *** (full error: http://fpaste.org/139382/25324161/) It seems like it's blowing up on grub2-probe, as I can generate the same error. I tried specifying the device: 0 root@an-nas02:~# df -hP |grep boot /dev/mapper/an--nas02_vg0-lv_boot 506M 133M 373M 27% /boot 0 root@an-nas02:~# lvdisplay /dev/an-nas02_vg0/lv_boot |grep VG VG Name an-nas02_vg0 0 root@an-nas02:~# pvdisplay /dev/md0 | grep -e "VG Name" -e "PV Name" PV Name /dev/md0 VG Name an-nas02_vg0 0 root@an-nas02:~# cat /proc/mdstat |grep md0 md0 : active raid1 sdg2[1] sdh2[0] 0 root@an-nas02:~# ls -lah /dev/mapper/an--nas02_vg0-lv_boot lrwxrwxrwx. 1 root root 7 Oct 5 18:45 /dev/mapper/an--nas02_vg0-lv_boot -> ../dm-2 0 root@an-nas02:~# ls -lah /dev/dm-2 brw-rw----. 1 root disk 253, 2 Oct 5 18:45 /dev/dm-2 0 root@an-nas02:~# grub2-probe -d /dev/dm-2 *** Error in `grub2-probe': double free or corruption (fasttop): 0x0000000001e9cfd0 *** ======= Backtrace: ========= /lib64/libc.so.6(+0x7d1ad)[0x7f9c702da1ad] <snip> Full error: http://fpaste.org/139387/41253399/ So I am wondering how I can make /dev/sdg bootable? A RAID 1 array is of limited use if I can only boot off of one of the disks. :) Thanks! -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?

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VMWare Workstation Guest Keep Crashing
by Igal ＠ getRailo.org 05 Oct '14

05 Oct '14

hi all, I've inherited a CentOS 6.4 machine that runs VMWare Workstation 9 which in turn hosts a Windows SBS 2011 guest. the problem is that the Windows guest keeps crashing, and I have no idea why. it was working fine for a while but recently started crashing after a day or two of operation. as a total Linux/CentOS noob, I have some questions: 1) is it safe to assume that since the guest crashes, but not the host, then the issue is with the Windows setup and not the CentOS? 2) any ideas how I would go to find the problem? 3) I understand now that a better virtualization would be KVM or Xen. any word of advice on which is better if the host machine need only run the guest OS and back it up? TIA! -- Igal Sapir Railo Core Developer http://getRailo.org/

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Re: [CentOS] [exim] how to check a message header for being empty
by Always Learning 05 Oct '14

05 Oct '14

On Sun, 2014-10-05 at 12:51 +0100, Dennis Davis wrote: > On Sat, 4 Oct 2014, lee wrote: > > > Is the Subject: header required by some RFC? If it is, I'll also > > deny messages that don't have one. > Not as far as I'm aware. RFC5322, "Internet Message Format", > contains: > > The only required header fields are the origination date field and > the originator address field(s). All other header fields are > syntactically optional. More information is contained in the table > following this definition. There is a real difference between the lack of a Subject: header and a present but empty Subject: header. I reject emails with no Subject: headers but accept empty Subject: headers because even I can occasionally forget to type-in a Subject. -- Regards, Paul. England, EU.

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Respective Roles of NetworkManager.service and Network.service
by Richer, Mark (CIV) 05 Oct '14

05 Oct '14

I know folks have different opinions about Network Manager, but while researching how to change the name of a NIC without rebooting, I also came across the following page from RedHat that I’ll share as I find it’s very clear and concise explanations on how these services interact on CentOS/RHEL 7: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/ht… It answered my question as to whether it’s appropriate to have both services running and apparently this is fine, but not necessary depending on how you configure networking. Mark MARK H RICHER, MS CS NPS-NCR Digital Forensics Lab IT Manager Computer Science Department Naval Postgraduate School - National Capital Region (NCR) 900 N Glebe Rd, Rm 5-182, Arlington, VA 22203 571.858.3254 (o) 571.303.9498 (m) mhricher(a)nps.edu<mailto:mhricher@nps.edu>

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how2 mount ntfs partition that is part of a full HD image file
by Fred Smith 05 Oct '14

05 Oct '14

I have a full disk image file (courtesy of ddrescue), and need to mount one of its partitions. I suppose I should have just extracted the single partition when I was using ddrescue, but right now I have the whole disk instead, and no disk space left to re-do the extraction (in fact I won't be able to use the system where I did it for several weeks, so I'd love to be able to mount just the partition from the image I have). I'll be doing some digging, but thought I'd inquire here too. thanks in advance! -- ------------------------------------------------------------------------------- Under no circumstances will I ever purchase anything offered to me as the result of an unsolicited e-mail message. Nor will I forward chain letters, petitions, mass mailings, or virus warnings to large numbers of others. This is my contribution to the survival of the online community. --Roger Ebert, December, 1996 ----------------------------- The Boulder Pledge -----------------------------

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Mounting LUNs from a SAN array - LUN mappings to devices in /dev/ - are they static?
by Rafał Radecki 04 Oct '14

04 Oct '14

Hi All :) I am currently involved in a project in which there is a SAN array (Sun Storagetek 2540) which exports LUNs for some servers with Centos 5.2 x86. I will be performing a migration to Centos 5.9 x86_64 in some time and am gathering needed info now :) I am trying to find the place in the OS where there is the information about LUN mappings to /dev/ devices. For example on array level I have an exported LUN with number 8. I see it on one of the servers with lsscsi as: # lsscsi | grep '7\:0\:0\:8' [7:0:0:8] disk SUN LCSM100_F 0735 /dev/sdj As I said I need to perform migration of the OS to Centos 5.9 x86_64 and am curious where from does the mapping scsi device 7:0:0:8 <-> /dev/sdj come? I have some complex logical volume (Veritas Volume Manager) setup based on /dev/ disks (which are derived from LUNs imported from the array) and will need to recreate it on destination servers. My coworker said that udev may be assigning the /dev/sdj (and other) identifier so I checked this. In /etc/udev/rules.d/* I see rules for scsi subsystem (sysfs type 0 is "disk"): ACTION=="add", SUBSYSTEM=="scsi", WAIT_FOR_SYSFS="ioerr_cnt" ACTION=="add", SUBSYSTEM=="scsi_device", SYSFS{type}=="0", RUN+="socket:/org/kernel/diskres/uevents" ACTION=="remove", SUBSYSTEM=="scsi_device", RUN+="socket:/org/kernel/diskres/uevents" So I do not see anything which could answer my question. There have been other rules for different sysfs types but I think they are not relevant in my case. In sysfs in /sys/bus/scsi/devices/7:0:0:8 I found: # ll block\:sdj lrwxrwxrwx 1 root root 0 Oct 4 17:57 block:sdj -> ../../../../../../../../../../block/sdj Where else can I look for the LUN<->/dev/ device mapping rules? How are the LUNs mapped to operating system devices? Is there a way to add a static mapping so that also on a new server after attaching SAN array LUN number 8 will be visible as /dev/sdj? I think that there is a possibility that on a new server mentioned LUN will be visible as a different /dev/sd? :( That could potentially break my logical volume setup on the destination server. Any info will be greatly appreciated :) BR, Rafal.

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Re: [CentOS] Mounting LUNs from a SAN array - LUN mappings to devices in /dev/ - are they static?
by Rafał Radecki 04 Oct '14

04 Oct '14

The answer is: I was told to do so :) Corpo related stuff ;) R. 2014-10-04 18:25 GMT+02:00 Reindl Harald <h.reindl(a)thelounge.net>: > > Am 04.10.2014 um 18:22 schrieb Rafał Radecki: > >> As I said I need to perform migration of the OS to Centos 5.9 x86_64 and >> am >> curious where from does the mapping >> >> scsi device 7:0:0:8 <-> /dev/sdj >> >> come? >> > > you must not rely on that mapping - never > it can and will change in many cases at every boot > that's why UUID's and labels exists > > P.S.: > why do you consider to migrate to a *not* supported and outdated > CentOS 5.9 - people need to realize that CentOS has only *one* > supported version, the latest one, 5.11 starting with this week > >

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en01 network
by Jerry Geis 04 Oct '14

04 Oct '14

I have installed CentOS 7. I added "biosdevname=0 net.ifnames=0" at install time. I still have a network name of en01 and not eth0. How do I get eth0 when viewing ifconfig? dmesg | grep eth0 show its being detected, and being renamed. systemd-udev renaming eth0 to en01... I then looked in /etc/udev and dont see anything of value... Thanks, Jerry

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Discuss October 2014