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Re: [CentOS] C8 and backup solution
by Alessandro Baggi 03 Apr '20

03 Apr '20

Il 02/04/20 21:14, Karl Vogel ha scritto: > [Replying privately because my messages aren't making it to the list] > >>> In a previous message, Alessandro Baggi said: > A> Bacula works without any problem, well tested, solid but complex to > A> configure. Tested on a single server (with volumes on disk) and a > A> full backup of 810gb (~150000 files) took 6,30 hours (too much). > > For a full backup, I'd use something like "scp -rp". Anything else > has overhead you don't need for the first copy. > > Also, pick a good cipher (-c) for the ssh/scp commands -- it can improve > your speed by an order of magnitude. Here's an example where I copy > my current directory to /tmp/bkup on my backup server: > > Running on: Linux x86_64 > Thu Apr 2 14:48:45 2020 > > me% scp -rp -c aes128-gcm(a)openssh.com -i $HOME/.ssh/bkuphost_ecdsa \ > . bkuphost:/tmp/bkup > > Authenticated to remote-host ([remote-ip]:22). > ansible-intro 100% 16KB 11.3MB/s 00:00 ETA > nextgov.xml 100% 27KB 21.9MB/s 00:00 ETA > building-VM-images 100% 1087 1.6MB/s 00:00 ETA > sort-array-of-hashes 100% 1660 2.5MB/s 00:00 ETA > ... > ex1 100% 910 1.9MB/s 00:00 ETA > sitemap.m4 100% 1241 2.3MB/s 00:00 ETA > contents 100% 3585 5.5MB/s 00:00 ETA > ini2site 100% 489 926.1KB/s 00:00 ETA > mkcontents 100% 1485 2.2MB/s 00:00 ETA > > Transferred: sent 6465548, received 11724 bytes, in 0.4 seconds > Bytes per second: sent 18002613.2, received 32644.2 > > Thu Apr 02 14:48:54 2020 > > A> scripted rsync. Simple, through ssh protocol and private key. No agent > A> required on target. I use file level deduplication using hardlinks. > > I avoid block-level deduplication as a general rule -- ZFS memory > use goes through the roof if you turn that on. > > rsync can do the hardlinks, but for me it's been much faster to create > a list of SHA1 hashes and use a perl script to link the duplicates. > I can send you the script if you're interested. > > This way, you're not relying on the network for anything other than the > copies; everything else takes place on the local or backup system. > > A> Using a scripted rsync is the simpler way but there is something that > A> could be leaved out by me (or undiscovered error). Simple to restore. > > I've never had a problem with rsync, and I've used it to back up Linux > workstations with ~600Gb or so. One caveat -- if you give it a really > big directory tree, it can get lost in the weeds. You might want to do > something like this: > > 1. Make your original backup using scp. > > 2. Get a complete list of file hashes on your production systems > using SHA1 or whatever you like. > > 3. Whenever you do a backup, get a (smaller) list of modified files > using something like "find ./something -newer /some/timestamp/file" > or just making a new list of file hashes and comparing that to the > original list. > > 4. Pass the list of modified files to rsync using the "--files-from" > option so it doesn't have to walk the entire tree again. > > Good luck! > > -- > Karl Vogel / vogelke(a)pobox.com / I don't speak for the USAF or my company > > The best setup is having a wife and a mistress. Each of them will assume > you're with the other, leaving you free to get some work done. > --programmer with serious work-life balance issues Hi Karl, thank you for your answer. I'm trying ssh scripted rsync using a faster cypher like you suggested and seems that transfer on 10GB is better of default selected cypher (129 sec vs 116 using aes128-gcm, I tested this multiple times). Now I will try to check on the entire dataset and see how much benefit I gain. Waiting that, what do you think about bacula as backup solution? Thank you in advance.

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CentOS 7 host with guests as bridge cannot access host
by Jerry Geis 02 Apr '20

02 Apr '20

I have CentOS 7 host. Two guests on bridge network setup by GUI and virt-manager. 1 CentOS 8 guest 1 Win 10 guest Both cannot access the host. They can other machines on the network. Guests can access the internet just not the host. I used virt-manager GUi to set up everything. Selected the eth0:macvtap and Bridge. I "desire" bridge network. If I select something else I get access to host - but of course machine is not on the main network. Thoughts ? Jerry

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Re: [CentOS] Versions in RHEL and CentOS
by Peter Kjellström 02 Apr '20

02 Apr '20

On Thu, 2 Apr 2020 11:10:23 +0530 Thomas Stephen Lee <lee.iitb(a)gmail.com> wrote: ... > /usr/bin/sensors > > from the lm_sensors package > > I had run > > sensors-detect --auto I had no idea people still used that package. Especially on a server. Per core temperatures in linux for Zen2 is done using (a very up to date kernel with its k10temp module). Alternatively one can look at: https://github.com/ocerman/zenpower.git I don't know if it works with the c8 kernel (but it does not work with the c7 one). But in the end. Why care about per core temperatures? Setup basic monitoring of the server using ipmi or whatever the vendor supports. /Peter K

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Cloud Image building (like CentOS is doing it)
by Nicolas Ghirlanda 02 Apr '20

02 Apr '20

Hello, I was not able to find information about how CentOS is building its Cloud Images. I know packer etc are able to do it, but I am interested in how CentOS is building its own images as we like to adapt that for our Openstack Cloud. thanks for any hints Nicolas

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centos 6 vs 7
by Divine Tanyingoh 01 Apr '20

01 Apr '20

Issue: After installing vms on vmware, I noticed a difference in behavior between centos 6 vs 7. On centos 6 I cannot ping the hostname and get a reply without first resolving in the /etc/hosts file by adding a new entry: 192.168.0.47 server1.example.com. But for centos 7 I am able to ping the hostname and get a reply even when I have not made any changes to the /etc/hosts file. Why is there this difference between centos 6 vs 7. Thank you for your assistance.

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Qemu guest(s) in bridge mode cannot see host machine.
by Jerry Geis 31 Mar '20

31 Mar '20

Hi All - I have a Win10 and Centos 8 guest both that bridge mode does not see the host- other computers seem ok. They cannot even ping the host. My host is CentOS 7. I did some searching - I see the issue - but not what was done to resolve it ? Thanks, Jerry

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mlocate-updatedb.timer not working?
by Frank Cox 31 Mar '20

31 Mar '20

I set this computer up with Centos 8 a few days ago. "systemctl status mlocate-updatedb.timer" says "Active (waiting)". But the mlocate database hasn't been updated since the last time I ran updatedb manually. # ls -l /var/lib/mlocate/* -rw-r-----. 1 root slocate 22944208 Feb 29 10:30 /var/lib/mlocate/mlocate.db What have I missed? -- MELVILLE THEATRE ~ Real D 3D Digital Cinema ~ www.melvilletheatre.com

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Problem installing bind-dyndb-ldap
by Michal Zacek 31 Mar '20

31 Mar '20

Hello, is there a way, how to avoid this stupid "module" problem? Google didn't help, except it is quite common at Centos 8.1. [root@centos8 ~]# dnf install bind-dyndb-ldap ..... Running transaction check No available modular metadata for modular package 'bind-dyndb-ldap-11.1-14.module_el8.1.0+253+3b90c921.x86_64', it cannot be installed on the system [root@centos8 ~]# cat /etc/redhat-release CentOS Linux release 8.1.1911 (Core) Thanks, MZa

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Versions in RHEL and CentOS
by Thomas Stephen Lee 30 Mar '20

30 Mar '20

Hi, I had a doubt regarding RHEL/CentOS Versions. https://access.redhat.com/support/policy/amd in the he Notes No (8) says "Update 2 of Red Hat Enterprise Linux 8" does it mean it will appear in CentOS 8.2, or is already there from 8.0 ? thanks -- Lee

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CentOS 8 Gstreamer and Mplayer
by Mark LaPierre 30 Mar '20

30 Mar '20

Hey Y'all, What replaced Gstreamer and Mplayer in CentOS 8. RPM finder finds both for CentOS 6 and 7 but not 8. There must be a replacement for them but I don't know what. I appear to be having codec issues but, not knowing what's supposed to handle the jobs that the two programs used to do, I don't know where to look for a commercial set of codecs compatible with the application. I'm getting error messages, "No video with supported format and MIME type found." when visiting certain web sites with Firefox. I would try it with Chrome but that does not appear to be available in the CentOS 8 repos either. I found solutions to this issue on the net that involved turning off HTML5 direct rendering and using Flash, but that's not going to happen. -- _ °v° /(_)\ ^ ^ Mark LaPierre Registered Linux user No #267004 https://linuxcounter.net/ ****

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