Discuss March 2021

discuss@lists.centos.org

73 participants
56 discussions

Bare metal vs. virtualization: Proxmox + Ceph + CentOS ?
by Nicolas Kovacs 14 Mar '21

14 Mar '21

Hi, Last week I had a disaster which took me a few unnerving days to repair. My main Internet-facing server is a bare-metal installation with CentOS 7. It hosts four dozen web sites (or web applications) based on WordPress, Dolibarr, OwnCloud, GEPI, and quite a number of mail accounts for ten different domains. On sunday afternoon this machine had a hardware failure and proved to be unrecoverable. The good news is, I always have backups of everything. In that case, I have a dedicated backup server (in a different datacenter in a different country). I’m using Rsnapshot for incremental backups, so I had all data: websites, mail accounts, database dumps, configurations, etc. Now here’s the problem: it took me three and a half days of intense work to restore everything and get everything running again. Three and a half days of downtime is quite a stretch. As far as I understand, my mistake was to use a bare-metal installation and not a virtualized solution where I could simply restore a snapshot of a VM. Correct me if I’m wrong. Now I’m doing a lot of thinking and searching. Proxmox and Ceph look quite promising. From what I can tell, the idea is not to use a big server but a cluster of many small servers, and aggregate them like you would do with hard disks in a RAID 10 array for example, only you would do this for the whole system. And then install one or several CentOS 7 VMs on top of this setup. Any advice from the pros before I dive head first into the documentation? Cheers from the sunny South of France, 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 Mob. : 06 51 80 12 12

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Re: [CentOS] Dual WAN on EL8 desktop.
by Gordon Messmer 14 Mar '21

14 Mar '21

On Mon, Feb 15, 2021 at 10:30 PM Thomas Stephen Lee <lee.iitb(a)gmail.com> wrote: > What is ideal is the bandwidth of two connections and half bandwidth > when one link is down. That may not be *generally* possible. You can load-balance your network streams (connections), so that you'll utilize the bandwidth of two physical links in sum, but each individual network stream is going to traverse just one physical link, and will never be faster than whichever link is selected for that stream when it is initiated.

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Re: [CentOS] Dual WAN on EL8 desktop.
by Thomas Stephen Lee 12 Mar '21

12 Mar '21

On Wed, Feb 17, 2021 at 2:04 AM Kenneth Porter <shiva(a)sewingwitch.com> wrote: > > --On Tuesday, February 16, 2021 12:00 PM +0530 Thomas Stephen Lee > <lee.iitb(a)gmail.com> wrote: > > > The solution should be a software one without acquiring new hardware. > > What is ideal is the bandwidth of two connections and half bandwidth > > when one link is down. > > The search term you're looking for is "NIC bonding". Here's the first hit I > get from Google: > > <https://www.enterprisenetworkingplanet.com/linux_unix/article.php/3850636/U…> > Hi, I tried https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/ht… without success I have a feeling that bonding is for interfaces on the same network, not two internet routers. Please correct me if I'm wrong. --- Lee

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Disk read io very high, but no process perform io read
by yf chu 12 Mar '21

12 Mar '21

We have experienced a very weird problem. The load of the server machine is very high. We use "pidstat" and find that the disk read io is very high. But the processes running on this server do not perform any disk read operation. We also noticed that when we execute "top" command, for most of processes, the values in "SHR" column are zero. Compared with other normal servers, we found that by executing "free -m", the result shows that the buff/cache value in this server is lower than the value of other normal servers. We also found that there were lots of major page faults by executing "ps -o majflt,minflt". Swap is not enabled on this server. What could be the reason for this issue? The centos version:CentOS Linux release 7.3.1611 kernel version:3.10.0-693.21.1.std7a.el7.0.x86_64

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R730xd & SD card identfication
by Gregory P. Ennis 10 Mar '21

10 Mar '21

Everyone, We have migrated a platform to a Centos 8 host using kvm guest machines Recently I tried to copy one of the guests to the external SD card on the back of the Dell R730xd, but I have not been able to get the Centos 8 host to recognize the SD card. I can use DRAC interface of the R730xd to see that the SD card is being recognized and the status of the external SD slot is turned from inactive to active when the card is inserted. I have used lsblk, fdisk -l, and 'dmesg | tail' none of which demonstrate that the Centos 8 host is recognizing the SD card. You help would be appreciated. Thanks !! -- Greg Ennis

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SHR in top command is zero and major page fault is frequent
by yf chu 08 Mar '21

08 Mar '21

Recently, I found that many processes in our server experienced high frequency of major page faults. The disk IO on this server is also very high. I also noticed that when I execute "top" command, for some processes, the value in SHR column became zero. when I restart these processes, the values of SHR became non-zero again. What could be the reason for frequent major page fault? Is there any connection between zero SHR and major page fault?

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kernel-devel package newer than installed kernel
by Mauricio Tavares 08 Mar '21

08 Mar '21

Running CentOS Linux release 8.3.2011 According to uname my kernel is 4.18.0-240.10.1.el8_3.x86_64, but when I check which version of kernel-devel is available, yum info kernel-devel I get that Source : kernel-4.18.0-240.15.1.el8_3.src.rpm Why is the version of kernel-devel available for my kernel based on a newer kernel?

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Electron for CentOS 7
by H 08 Mar '21

08 Mar '21

I am trying to find electron for CentOS 7 but "yum provides electron\*" turns up nothing and pkgs.org does not find anything (https://pkgs.org/search/?q=electron) Does anyone have better information?

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mkdtemp on CentOS 7
by H 07 Mar '21

07 Mar '21

I am trying to compile DeltaChat in a CentOS 7 docker container and at one stage have to run: npm install --global electron but the above fails, seemingly because CentOS 7 does not have 'mkdtemp', nor have I found it in a repository. I had previously used: npm install electron --save-dev which installs fine but does not seem to use mkdtemp. yum provides mkdtemp ends up not finding anything but perhaps someone knows this better?

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proper recipe for local mirror
by Adrian Sevcenco 06 Mar '21

06 Mar '21

Hi! What is the proper solution for a local mirror for centos 7 (or oven 8) repositories? trying with rsync, while the packages are downloaded but the repodata is not and is actually impossible to be used by clients. while i try to recreate the repodata with createrepo -C -d --workers=4 ${repo} where ${repo} is the sync destination where it contains %arch/{Packages,repodata} directories the clients throw errors like: <LOCAL_MIRROR>/mirrors/centos/7/updates/x86_64/repodata/51d63b04c8bb74c5d9f09ae65f763f319a69492d9a8fac5ea0bf9b63bf347c5c-primary.sqlite.bz2: [Errno 14] HTTP Error 404 - Not Found What am i missing? Thanks a lot! Adrian

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Discuss March 2021