Discuss September 2019

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107 participants
75 discussions

SSD for Centos SWAP /tmp & /var/ partition
by Keith Roberts 03 Sep '25

03 Sep '25

Has anyone actually used a SSD in a Centos setup? My little experiment with a s/h WD drive for /tmp and SWAP partitions kicked the bucket on Wednesday, when the poor WD drive caught the click-of-death. It was a s/h drive to start with and lasted about 4 months. But that was without the /var/log/ partition being written to it, as I mounted that back onto /var/log from the original drive. So I had to install another (WD) drive, and repartion it and rebuild my RPM package database, from the backed-up Packages file. That seems to be all OK now. I'm wondering if it would be a good idea to use a new SSD for moving all the disk i/o to, that Linux likes to do so often. Plus putting SWAP onto a decent SSD should speed things up somewhat. Here's a short video of a laptop fitted with a SSD drive booting macOS, compared to a similar laptop booting from the standard HDD. The laptop with the SSD boots and loads some apps in 28 seconds. The other one takes twice as long. http://eshop.macsales.com/shop/SSD/OWC/Mercury_Extreme_Pro_6G/?utm_source=t… Kind Regards, Keith Roberts ----------------------------------------------------------------- Websites: http://www.karsites.net http://www.php-debuggers.net http://www.raised-from-the-dead.org.uk All email addresses are challenge-response protected with TMDA [http://tmda.net] -----------------------------------------------------------------

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Issues booting centos7 [dracut is failing to enable centos/root, centos/swap LVs]
by Yannis Milios 01 Feb '25

01 Feb '25

Hello, I'm having a strange problem booting a new centos7 installation. Below some background on this. [I have attached the tech details at the bottom of this message] I started a new CentOS7 installation on a VM, so far all good, o/s boots fine. Then I decided to increase VM disk size (initially was 10G) to 13G. Powered off the VM, increased the vhd via the hypervisor, booted from CentOS livecd, selected "recover my centos installation". Then I used the following sequence of commands to make the new vhd size "visible" to the o/s ... - ran fdisk /dev/sda and deleted partition 2. (This is the LVM partition where the o/s is stored. The first partition is /boot [xfs] partition *non lvm*.) - created a new partition with same starting sector as before deleting it, but a different ending sector (to reflect to the increased space). - set partition type to 8e (lvm), saved settings and exit. - ran pvresize and lvresize to make new space visible to the o/s.All good, I can see the space increase on 'lvdisplay centos/root'. - ran 'mount /dev/mapper/centos-root /mnt/root' to temporarily mount the o/s partition. - ran 'xfs_growfs /mnt/root' to resize the o/s fs to the new size. It was successful and I could actually chroot to the o/s and verify new disk size. - rebooted and tried to boot from hdd this time. Grub menu shows up and loads default kernel (3.10.0-862.9.1.el7.x86_64). - after initial kernel boot up process, booting continues to initrd and then it's where the problem starts... - looks like dracut has issues locating/enabling /dev/mapper/centos-root (lv) and as a result it cannot boot to the 'real' root fs (/). - while in dracut shell, I execute the following command sequence: 1. lvm lvchange -ay /dev/centos/root 2. lvm lvchange -ay /dev/centos/swap 3. ln -s /dev/mapper/centos-root /dev/root 4. exit ...and the o/s boots fine...so looks like the pv,vg,lv is detected properly while in initrd, but somehow dracut has difficulties enabling the root,swap LVs ? - While in o/s, I rebuild initrd by using: 'dracut -f -v -a lvm' Note, I have to use '-a lvm' as for some reason, if don't, the lvm utils (lvm,lvm_scan) are not being included to the initrd, not sure why this happens. After rebooting, same thing happens, I have to manually boot the system via dracut shell. I'm a bit stuck at this point, any clues what I'm doing wrong in here ? As I previously said, this is a new installation, so I could simply reinstall the whole thing, but I would rather try to find out some answer to why is this happening ... :-) [curiosity] Some additional details: ================== I've attached /run/initramfs/rdsosreport.txt file [generated while in inird] here: https://privatebin.net/?fdc4052c0c402884#gdB/QYR3IeR55SxUbjfrkZPQfJ7jMxiUxq… o/s ver=CentOS Linux release 7.5.1804 (Core) [root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 13G 0 disk ├─sda1 8:1 0 500M 0 part /boot └─sda2 8:2 0 12.5G 0 part ├─centos-root 253:0 0 11.5G 0 lvm / └─centos-swap 253:1 0 1G 0 lvm [SWAP] [root@localhost ~]# cat /etc/default/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=saved GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="rd.lvm.lv=centos/root rd.lvm.lv=centos/swap rd.shell rhgb" GRUB_DISABLE_RECOVERY="true"

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Brother HL-L2360DW printing quality
by H 23 Jul '20

23 Jul '20

I have the above printer but have not been able to resolve issues with the printing quality in CentOS 7. The test page prints fine but when I print PDF-documents, most recently using Chinese fonts, it is lacking and the pages very hard to read. The settings in the Mate Cups configuration panel are fine and set to 600 dpi, the settings in the printer menu are all OK yet it prints more like maybe 150 or even 75 dpi. Any suggestion what might be wrong?

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Re: [CentOS] upg. CentOS 7.5 to 7.6: unable to mount smb shares - samba NT domain member using ldap
by Gordon Messmer 27 Jan '20

27 Jan '20

On 1/2/19 12:09 PM, Miroslav Geisselreiter wrote: > some parameters from smb.conf: > [global] > workgroup = NT4DOMAIN > netbios name = nt4member > security = domain > passdb backend = ldapsam:"ldap://ldap1server.intranet.xx > ldap://ldap2server.intranet.xx" I'm not sure it makes sense to use "security = domain" with an ldap passdb backend. If you're using a real NT4 domain, then you shouldn't need a passdb backend at all. If you're not in an NT4 domain, then you should set "security = USER". The man page for smb.conf notes "This mode will only work correctly if net(8) has been used to add this machine into a Windows NT Domain." Did you add this host to a Windows NT domain, using "net join ..."?

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CentOS 7.6 1810 vs. VirtualBox : bug with keyboard layout selection
by Nicolas Kovacs 20 Jan '20

20 Jan '20

Hi, I'm currently working on my next Linux book, which will be an elementary course about CentOS administration. I'm using VirtualBox for all the installer screenshots. Since CentOS has recently been upgraded to version 7.6, I thought I might as well base all book references on this version. So I downloaded the 7.6 1810 minimal ISO and started a fresh installation in VirtualBox. I'm using a Swiss French keyboard layout (ch-fr or fr_CH-latin1), so one of the first things I do in the installer is replace the default French AZERTY keyboard (since I use the french language) by a swiss french QWERTZ layout. Now when I reach this dialog in the installer and try do define my new layout, the slider in the selection window doesn't appear, and clicking on any of the first layouts doesn't do anything, so I'm basically stuck there. I'm running OpenSUSE Leap 15.0 KDE on my workstation, so I tried the same thing with the previous CentOS 7.5 1804 minimal ISO, and the keyboard selection dialog works perfectly. So my intuition would tell me that there's a nasty bug in the CentOS 7.6 installer. Maybe it went unnoticed, since most folks stick to the default keyboard layout selected in their language. Any suggestions ? Cheers, Niki -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Site : https://www.microlinux.fr Blog : https://blog.microlinux.fr Mail : info(a)microlinux.fr Tél. : 04 66 63 10 32

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CentOS 7 as a Fibre Channel SAN Target
by Steffan A. Cline 02 Jan '20

02 Jan '20

For quite some time I’ve been using FreeNAS to provide services as a NAS over ethernet and SAN over Fibre Channel to CentOS 7 servers each using their own export, not sharing the same one. It’s time for me to replace my hardware and I have a new R720XD that I’d like to use in the same capacity but configure CentOS 7 as a Fibre Channel target rather than use FreeNAS any further. I’m doing virtualization and this will allow me to have failover from one node to the other since they’ll all be sharing the same export rather than me simply backing up to the FreeNAS server the way I am now. Does anyone know of any really good current articles that explain how to set up CentOS 7 as the target in such a configuration and also setting up CLVMd so they can all share an export over Fibre Channel from CentOS 7? Steffan A. Cline steffan(a)hldns.com 602-793-0014

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browsers slowing Centos 7 installation to a crawl
by Michael Hennebry 04 Dec '19

04 Dec '19

My video problems mentioned in a previous thread are gone, though I do not know why. Now my problem is that whenever I have a browser open and an internet connection, my Centos 7 slows to a crawl. Chromium seems to be the least bad. Sometimes it slows to the point that I cannot even move the mouse. Even switching between virtual terminals takes a while sometimes. When I get there, top generally shows me between two and five D states. I've changed service providers lately. The problem survived the change. Some sites seem to aggravate the problem. Most recently, a site tried to connect to c.amazon.adsystem.com . I got the message waiting for c.amazon.adsystem.com . I have that address in my hosts file as 127.0.0.1 . ping finds it and pings. nslookup does not: > [hennebry@localhost ~]$ nslookup c.amazon.adsystem.com > Server: 192.168.0.1 > Address: 192.168.0.1#53 > > ** server can't find c.amazon.adsystem.com: NXDOMAIN Whether the slow-to-crawl problem is related to the failure to redirect, I do not know. The former is clearly more important. Any suggestions on how to diagnose it? Any ideas on why chromium is waiting for c.amazon.adsystem.com and how I can fix it? -- Michael hennebry(a)web.cs.ndsu.NoDak.edu "Sorry but your password must contain an uppercase letter, a number, a haiku, a gang sign, a heiroglyph, and the blood of a virgin." -- someeecards

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CentOS7 sometimes don't detect NIC after reboot
by Miroslav Geisselreiter 20 Nov '19

20 Nov '19

I have brand new PC with this components: CPU Intel® Pentium G5400, LGA1151 motherboard ASUS PRIME B360M-C 16 GB RAM HDD 2x ADATA SSD 256GB XPG GAMMIX S11, PCIe Gen3x4 M.2 2280 (RAID1) NIC Intel X550-T1 Ethernet Converged Network Adapter I installed CentOS 7 and two NICs were detected: eno1 (on motherboard) enp1s0 (Intel X550-T1) When I restart the machine sometimes enp1s0 is missing. It is not detected during boot. It looks like NIC card is not installed / not present. After next reboot everything is fine and I do not see any problems with NIC card. How can I avoid this problem with missing NIC? Can you help me, please? Miroslav Geisselreiter

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Centos 8 Mate?
by Frank Cox 28 Oct '19

28 Oct '19

Without wanting to sound too pushy, I'm wondering if there is any update on the status of Mate now that Centos 8 has been released? I would love to jump on C8 and start playing with it, but the lack of Mate is kind of a showstopper for me at the moment. -- MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com

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UEFI and PXE
by isdtor 25 Oct '19

25 Oct '19

We have a working PXE setup. I've tried to adapt it to UEFI as per RHEL6 manual, but the client won't boot. Strangely, tcpdump shows that the client tries to download all files via tftp from the dhcp server rather than the tftp server (they are different). next-server is pointing to the tftp server. Any clues?

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Discuss September 2019