Re: [CentOS] CentOS 6.9, shredding a RAID
Gordon Messmer wrote: > On 05/31/2017 08:04 AM, m.r...@5-cent.us wrote: >> I've got an old RAID that I attached to a box. LSI card, and the RAID >> has 12 drives, for a total RAID size of 9.1TB, I think. I started shred >> /dev/sda the Friday before last... and it's still running. Is this >> reasonable for it to be taking this long...? > > Was the system booting from /dev/sda, or were you running any > binaries/libraries from sda? Often you'll be able to shred the device > you boot from, but you won't get a prompt back when it's done. No, the h/w RAID showed up as sda when I booted; / showed up on sdb. mark ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 6.9, shredding a RAID
On 05/31/2017 08:04 AM, m.r...@5-cent.us wrote: I've got an old RAID that I attached to a box. LSI card, and the RAID has 12 drives, for a total RAID size of 9.1TB, I think. I started shred /dev/sda the Friday before last... and it's still running. Is this reasonable for it to be taking this long...? Was the system booting from /dev/sda, or were you running any binaries/libraries from sda? Often you'll be able to shred the device you boot from, but you won't get a prompt back when it's done. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] more recent perl version?
On Jun 2, 2017, at 5:05 AM, hw wrote: > > Warren Young wrote: >> >> There are various options. We use mod_fcgid + Plack here. > I need to look into that when I have time. I wonder if it wouldn’t have been faster to just backport the app to Perl 5.16? How hard could it be? It’s not like Perl 5.16 is a hopelessly lame and incapable language. The recommendation to replace mod_perl with mod_fcgid comes from the RHEL 7 release notes: http://goo.gl/fZxHw9 After sending that message, I remembered that we rejected that option once we found out that when you build your app under Plack, it serves content via a Perl web server using a standard interface called PSGI. That Perl web server normally binds to localhost on a high-numbered TCP port, so we just stood Apache up in front of it as a reverse proxy. That avoids the security hassles of binding to TCP port 80, and it lets us foist the static content serving load off on Apache, so that the Perl layer serves only dynamic content. There are many PSGI-aware web servers: http://plackperl.org/#servers The default used by Plack is HTTP::Server::Simple, which is probably fast enough for your purposes if CGI remains appropriate for your app. If you were already trying to get off CGI to make the app faster, many of the alternatives in that list will get you that speed. The mod_fcgid method may be easier to port to, since you’re already using CGI, however. > Test have shown that > lighttpd apparently is somewhat faster than apache2 This is generally true only at fairly high loads, up in the thousands of connections per second. Distinguishing this also requires that the bottleneck be in the web server, not in the web app it’s serving. Since your app is currently running via CGI, one of two conditions is true: 1. You have chosen well: CGI is appropriate for your application, in which case all web servers with the features you need are interchangeable, because the bottleneck is CGI, not the web server. 2. You have chosen poorly: CGI is slowing your app down enough that end users notice the speed hit, in which case you need to get off CGI before you start chasing nonstandard web servers, because speeding up the web server won’t solve the primary bottleneck. (“Nonstandard” meaning that lighttpd is not in the stock CentOS 7 repos. You have to reach out to EPEL to get it.) This is not to say that different web servers don’t have advantages even in the CGI case. I run nginx in one extra-small VPS because I don’t have the RAM to run Apache. I couldn’t put enough load on that server to tell any speed difference between Apache and nginx without running it out of CPU or network bandwidth first. > it can be difficult to run systems using ancient software. “You keep using that word. I do not think it means what you think it does.” — Inigo Montoya ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] should NUMA be enabled?
-Original Message- From: CentOS [mailto:centos-boun...@centos.org] On Behalf Of hw Sent: Friday, June 2, 2017 9:27 AM To: CentOS mailing list Subject: [CentOS] should NUMA be enabled? > should NUMA be enabled in the BIOS of a server that has > two sockets but only a single CPU in one of the sockets? > > From what I´ve been reading, it is unclear to me if NUMA > should be enabled only on systems with multiple CPUs in > multiple sockets or if multiple cores of a single CPU in > a single socket benefit from NUMA being enabled, and if > memory access in general benefits from NUMA being enabled > (in some other ways) even when there is only a single > CPU in a single socket. > > It seems clear that NUMA should be enabled an can be taken > advantage of when there are multiple CPUs in multiple sockets. It matters when you have more than one physical CPU. Read the Wikipedia article describing it and might become more clear. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] should NUMA be enabled?
Hi, should NUMA be enabled in the BIOS of a server that has two sockets but only a single CPU in one of the sockets? From what I´ve been reading, it is unclear to me if NUMA should be enabled only on systems with multiple CPUs in multiple sockets or if multiple cores of a single CPU in a single socket benefit from NUMA being enabled, and if memory access in general benefits from NUMA being enabled (in some other ways) even when there is only a single CPU in a single socket. It seems clear that NUMA should be enabled an can be taken advantage of when there are multiple CPUs in multiple sockets. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [CentOS 6] Possible bug in updating glibc?
On Fri, Jun 02, 2017 at 06:40:57AM -0400, Leam Hall wrote: > I'm running a KVM host on updated CentOS 6. The guest is built from the > CentOS 6.9 dvd1 with just @base and @core package groups. > > When I went to install mysql it failed due to incompatibilities with the > libcc versions. Updated just glibc and glibc-common and then installed > mysql. Shortly there after it started to freeze and lost connection. > > The KVM host is fairly beefy and mysql wasn't doing anything but running > with no queries or data. I rebooted the guest and it still had lock up > issues. > > When I rebuilt the guest and did a full yum update, to include kernel and > kernel-headers, it seemed to run fine. > > It seems like there's a dependency between glibc(-common) and something > else. Or do I misunderstand? How did you update the software? If you had just run 'yum install mysql' it should have pulled in all the dependencies. Did you run a 'yum update' before trying to install mysql? Its possible that your mirrors are out of sync and your system is talking to a mirror with older RPMs, but without an actual error log, its hard to tell what's going on. -- Jonathan Billings ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] more recent perl version?
Nikolaos Milas wrote: On 2/6/2017 2:05 μμ, hw wrote: That´s a good thing, though it can be difficult to run systems using ancient software. You may want to check the following paradigm (from another open source perl-based application) to create a Perl environment within your system, avoiding to tamper with it: https://metacpan.org/pod/App::Netdisco#Installation That´s for network monitoring. We are running it in production for years and has been great in maintenance and operation (despite my initial fears). Alternatively, you can use a container. See for example: https://linuxcontainers.org/ http://www.itzgeek.com/how-tos/linux/centos-how-tos/setup-linux-container-with-lxc-on-centos-7-rhel-7.html http://www.perlmonks.org/index.pl?node_id=1034720 Containers are a bit quirky; I´m running two at home and one of them every now and then gets its /dev/null deleted on reboots, which causes trouble. I wouldn´t want that to happen here. Networking capabilities are also limited. Other than that, I agree that it would probably be better to use a container for the purpose rather than another VM. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] yum install does not downgrade
Personally, I would do one of three things:
1. Use the -m command to run 'yum install ' which /might/ work.
2. Uninstall the newer package and install the version you want. (Check
the 'state' directive to do this.)
3. Pin that package version when creating the server/VM so as not to be
updated.
#3 is useful to us as we kickstart all our servers and VMs, and this
eliminates the problem going forward. Then, when we're ready to upgrade
the pinned package, we have an ansible playbook that unpins that
version, installs the new version (even if not latest), then re-pins.
HTH.
On 06/01/2017 03:46 PM, Anand Buddhdev wrote:
We're using ansible to configure our CentOS 6 servers, and we have a
task to install a specific version of a package:
- name: install thrift2
yum: name=ripencc-thrift2-{{ version }}
In this ansible task, the "version" variable is set by the operator.
When we want to upgrade, it works. But today we had to downgrade, and
noticed that ansible wasn't downgrading it. So we tried by hand (the
installed version was 1.0.8):
# yum install ripencc-thrift2-1.0.3
I don't have the output handy, because a colleague was working on it,
but basically, yum said something like "package already installed" and
refused to downgrade it, even though the package is in our repository.
I have a strong sense that yum _used to_ downgrade packages if asked to
install an older version, but perhaps I am misremembering.
Nevertheless, I want to ask: is this a bug in yum? If asked to install a
specific version, should it not upgrade OR downgrade as needed?
Regards,
Anand
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Re: [CentOS] more recent perl version?
On 2/6/2017 2:05 μμ, hw wrote: That´s a good thing, though it can be difficult to run systems using ancient software. You may want to check the following paradigm (from another open source perl-based application) to create a Perl environment within your system, avoiding to tamper with it: https://metacpan.org/pod/App::Netdisco#Installation We are running it in production for years and has been great in maintenance and operation (despite my initial fears). Alternatively, you can use a container. See for example: https://linuxcontainers.org/ http://www.itzgeek.com/how-tos/linux/centos-how-tos/setup-linux-container-with-lxc-on-centos-7-rhel-7.html http://www.perlmonks.org/index.pl?node_id=1034720 Cheers, Nick ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] kvm/qemu and CPU load
Hi, I have a server using its 4 physical network interfaces bonded, with the bonding interface added to a bridge. The bridge has the IP, and three VMs are using the bridge. Two of the VMs are running Debian, one is running Windoze 7. CPU load caused by the qemu-kvm processes is way higher than I´m happy with. One of the Debian machine causes around 22% while it´s basically idle, the other one is around 3%, and the Windoze one is around 50. They are all mostly idle. I can observe that when some network traffic is going on with the Windoze machine, it causes a CPU load of 200%. "Some network traffic" means that virt-top is showing 1M/2M RX/TX. Considering that the bonding interface is theoretically capable of handling 4Gbit full duplex, the 3Mbit are neglectable. Virtio drivers are being used. Currently, virt-top shows 1.9% CPU for the Windoze machine and top shows 22% CPU load for the corresponding qemu-kvm process. There is almost not network traffic. The VM has 4 CPUs assigned. What may cause the high CPU load? Something must be seriously wrong for an idle machine causing 22% CPU load and for the same machine, still basically idle, with a some network traffic to cause 200% CPU load on a Xeon 5690. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] more recent perl version?
Warren Young wrote: On May 24, 2017, at 1:58 PM, hw wrote: It seems that lighttpd uses the perl version that is assigned in the configuration This is one of the advantages of Plack vs mod_perl, by the way: decoupling the Perl version from the web server version. while ignoring the LIBRARY_PATH variable set with mod_setenv Are you certain you don’t mean LD_LIBRARY_PATH here? https://stackoverflow.com/questions/4250624/ I was looking at the output of 'env' when perl524 was enabled and verified that when having LIBRARY_PATH set in the shell, the library is being found. It would require further testing to find out if setting LD_LIBRARY_PATH makes a difference. However, I even created a symlink to the library and it still couldn´t be loaded, so this is just weird. Even with a shell script as wrapper that sets and exports LIBRARY_PATH, perl can not find the library. Trying to set LIBRARY_PATH for lighttpd through systemd also doesnīt work. Beware that some layers of the OS actively redefine LD_LIBRARY_PATH in order to avoid security exploits. I wouldn’t be surprised if systemd did that in some cases, for good cause. It needs to at least present a warning it decides to override things explicitly set by the admin, like in a unit file. Anyway, I´ve given up on this, and the current plan is to use a VM or another machine with a different distribution to provide the service. That will probably be Debian, and we have a VM running Debian anyway, so I might just use that. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] more recent perl version?
Warren Young wrote: On May 24, 2017, at 9:38 AM, hw wrote: Warren Young schrieb: On May 24, 2017, at 7:05 AM, hw wrote: apache uses mod_perl mod_perl was dropped from Apache in 2.4, and Red Hat followed suit with RHEL 7. What is it using instead? There are various options. We use mod_fcgid + Plack here. I need to look into that when I have time. Test have shown that lighttpd apparently is somewhat faster than apache2, and I´m planning to use it instead of apache for what apache is doing atm. And atop that, Dancer, if you care. http://perldancer.org/ Join me on the Dancer ML if you want to talk further about it. I hope this does not strike you as inconsistent with respect to my prior posts, since that would be to construct a false equivalence between abandoned software and maintained stable software that is getting no new features. Not at all --- the point is that software usually becomes abandoned once a more recent version becomes available. And that’s what we keep trying to tell you: in the RHEL/CentOS world, that simply is not the case, because there is a multibillion-dollar entity ensuring that it is not so. That´s a good thing, though it can be difficult to run systems using ancient software. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] NFS mount on Centos 7 crashing
On 2/6/2017 10:58 πμ, Nikolaos Milas wrote: Have you checked if this bug/behavior has been reported or should we file a bug report? After a bit of search, I found the associated reports: https://bugs.centos.org/view.php?id=13351 https://bugzilla.redhat.com/show_bug.cgi?id=1454876 No solution yet, but -as a workaround- it seems that -at least- nfs problems are indeed solved with downgrading. Cheers, Nick ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] [CentOS 6] Possible bug in updating glibc?
Hey all, not sure if this was operator error or what. I'm running a KVM host on updated CentOS 6. The guest is built from the CentOS 6.9 dvd1 with just @base and @core package groups. When I went to install mysql it failed due to incompatibilities with the libcc versions. Updated just glibc and glibc-common and then installed mysql. Shortly there after it started to freeze and lost connection. The KVM host is fairly beefy and mysql wasn't doing anything but running with no queries or data. I rebooted the guest and it still had lock up issues. When I rebuilt the guest and did a full yum update, to include kernel and kernel-headers, it seemed to run fine. It seems like there's a dependency between glibc(-common) and something else. Or do I misunderstand? Thanks! Leam ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] yum install does not downgrade
On 01/06/2017 22:29, Tate Belden wrote: > Use the 'downgrade' option. Thanks Tate. I know the "downgrade" option well. I wouldn't have posted my question if it were that simple. As I said previously, we use ansible, and its "yum" module invokes: yum install package-version-release I expect yum to honour this, and downgrade a package if necessary, but it's not doing that. Given the lack of opinions here, I'll file a bugzilla report and see what the maintainers say. Regards, Anand ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Upgrade 6 to 7
Il 01 Giu 2017 10:13 PM, "Jerry Geis" ha scritto: I found this site https://wiki.centos.org/TipsAndTricks/CentOSUpgradeTool Is this still the case - there is no upgrade path from 6 to 7 ? I have a few remote servers I'd like to upgrade (if possible). Thanks, Jerry It is supported, with some limitations, in rhel, so the same I think applies to CentOS. See here for rhel https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Migration_Planning_Guide/chap-Red_Hat_Enterprise_Linux-Migration_Planning_Guide-Upgrading.html#chap-Red_Hat_Enterprise_Linux-Migration_Planning_Guide-Upgrading_from_RHEL6 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] NFS mount on Centos 7 crashing
On 2/6/2017 10:40 πμ, Philippe BOURDEU d'AGUERRE wrote: Reverting to rpcbind-0.2.0-38.el7 solves the problem for me Thank you very much Philippe, I notice that I have upgraded to rpcbind-0.2.0-38.el7_3.x86_64 on May 26. Have you checked if this bug/behavior has been reported or should we file a bug report? Nick ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] NFS mount on Centos 7 crashing
Le 02/06/2017 à 08:41, Nikolaos Milas a écrit : Questions: * Is this a known issue/bug? I have same problem since last rpcbind package update (rpcbind-0.2.0-38.el7_3) * Have we possibly made any NFS misconfigurations (which however have not caused any errors for about a year now)? * What could we do to prevent the error from occurring again? Reverting to rpcbind-0.2.0-38.el7 solves the problem for me -- Philippe BOURDEU d'AGUERRE AIME - Campus de l'INSA http://aime-toulouse.fr/ 135 av. de Rangueil Tél +33 561 559 885 31077 TOULOUSE Cedex 4 - FRANCE Fax +33 561 559 870 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
