Discuss November 2013

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160 participants
171 discussions

heavy IO load when working with sparse files (centos 6.4)
by Ron E 31 Mar '15

31 Mar '15

Dear List, We have noticed a variety of reproducible conditions working with sparse files on multiple servers under load with CentOS 6.4. The short story is that processes that read / write sparse files with large "holes" can generate an IO storm. Oddly, this only happens with holes and not with the sections of the files that contain data. We have seen extremely high IO load for example copying a 40 or 80gb sparse file that only has a few gigs of data in it. Attempts to lower the io priority and cpu priority of these processes do not make any measurable difference. (ionice, nice) This has been observed with processes such as: cp rsync sha1sum The server does have to be under some load to reproduce the necessary conditions. The cases we have seen involve servers running 10-30 guests under kvm. Load is in acceptable norms when the processes are run, such as load avg 5-15 on a 24 core (12 core with HT enabled) server. We also verify before starting such a process that the spindle with the file we're working on is not being unduly hammered by another process. These servers have one hardware raid controller each (Dell H700 controller with write cache enabled) and multiple raid arrays (separate sets of physical spindles). Interestingly, the IO storm is not limited to the array / spindles where the sparse file resides but affects all IO on that server. We have looked extensively and not found any account of a similar issue. We have seen this on configurations that are 'plain vanilla' enough to think that this is not something specific to our environment. Wondering if anyone else has seen this and if any suggestions on gathering more data / troubleshooting. We wonder if we've found either a raid controller driver issue, an OS issue or some other such thing. What seems to point in this direction is that even with ionice -c3 which should prevent the process from using IO unless the storage is idle, an io storm which appears to saturate the entire raid bus on a given server can occur. Thanks in advance.

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Centos 6.4 on Xserve, IPMI error
by Arno B 31 Mar '15

31 Mar '15

Hello! I'm trying to install Centos 6.4 64 bit on this Xserve: http://www.everymac.com/systems/apple/xserve/specs/xserve-intel-xeon-2.8-ei… I got a bootloader from: http://blog.christophersmart.com/2009/07/23/linux-on-an-apple-xserve-efi-on… as none of the official Centos releases (full, minimal, network 64 bit) boot on this machine. They all crash when loading the bootx64.conf. I have built a USB stick with a working bootx64.efi, grub.cfg, together with an initrd and a vmlinuz from the isolinux folder. These seem to get me into booting a kernel until something called IPMI is starting to throw errors at me: Console: switching to colour frame buffer device 128x48 fb0: VESA VGA frame buffer device ipmi message handler version 39.2 IPMI System Interface driver. ipmi_si 0000:09:00.4: enable device (0002 -> 0003) ipmi_si 0000:09:00.4: PCI INT C -> GSI 16 (level, low) -> IRQ 16 ipmi_si: Adding PCI-specified kcs state machine ipmi_si 0000:09:00.7: enable device (0000 -> 0003) ipmi_si 0000:09:00.7: PCI INT D -> GSI 17 (level, low) -> IRQ 17 ipmi_si: Adding PCI-specified bt state machine ipmi_si: Trying PCI-specified kcs state machine at mem address 0x90841000, slave address 0x0 irq 16 IRQ 16/ipmi_si: IRQF_DISABLED is not guaranteed on shared IRQs Using irq 16 ipmi: Found new BMC (man_id: 0x00003f, prod_id: 0x0003, dev_id: 0x20) IPMI kcs interface initialized ipmi_si: Trying PCI-specified kcs state machine at mem address 0x90840000, slave address 0x0 irq 17 Refined TSC clocksource calibration: 2792.999 MHz. Switching to clocksource tsc IPMI BT: timeout in XACTION [ B_BUSY ] 1 retries left IPMI BT: timeout in XACTION [ B_BUSY ] failed 2 retries, sending error response IPMI: BT reset (takes 5 secs) IPMI BT: timeout in XACTION [ B_BUSY H2B ] failed 2 retries, sending error response IPMI: BT reset (takes 5 secs) IPMI BT: timeout in XACTION [ B_BUSY H2B ] failed 2 retries, sending error response IPMI: BT reset (takes 5 secs) IPMI BT: timeout in XACTION [ B_BUSY H2B ] failed 2 retries, sending error response IPMI: BT reset (takes 5 secs) IPMI BT: timeout in XACTION [ B_BUSY H2B ] failed 2 retries, sending error response IPMI: BT reset (takes 5 secs) then the screen goes to black and the machine doesn't respond to anything anymore... Can anyone please help me with this? Maybe just point me in a direction where to find a solution? I've been googling for a few days now without much results... thanks in advance Arno Beekman

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mixing MX and CNAME
by aurfalien 27 Aug '14

27 Aug '14

Hi, Has any one had problems with mail clients were your DNS is like this; doman.com MX 50 mail.domain.com domain.com MX 100 mail2.domain.com domain.com CNAME www.domain.com -aurf

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RH developer toolset
by Jerry Geis 13 Aug '14

13 Aug '14

I saw an article this morning about the RH developer toolset. basically it includes a couple of packages like PHP python mysql (etc) that are later packages than that included in the released version like a 6.4 for example. So instead of php 5.3 with patches it would be php 5.4 and so on. That is great for a couple packages - but what about more up to date libraries like glib. 6.4 is way behind on glib. Like a couple years behind. Are there any plans in the "toolset" to update core libraries also? Thanks, Jerry

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Create Virtual Machine via HTTP or FTP
by cbulist＠gmail.com 08 Jun '14

08 Jun '14

Hi, I'm trying to create a Virtual Machine using Network Install mode (I tried HTTP and FTP). The HTTP/FTP server where the installation files are located is the Host Machine. The URL that I'm using is: http://192.168.1.104/inst and the Automatic detect option detects the OS without problem. When the installation starts I got an error: Unable to retrieve http://192.168.1.104/inst/images/install.img I tried different path but I always get the same error. The host machine is a Centos 6.2 (2.6.32.-220.el6.x86_64) I really appreciate any help with this problem. Thanks in advance,

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rsyslog not loading relp
by Mauricio Tavares 30 Mar '14

30 Mar '14

centos 6.4, setup to be syslog server. Doing remote syslog using tcp works fine, so now want to add relp. I installed the rsyslog-relp package and told rsyslog.conf to use it: # RELP Syslog Server: $ModLoad imrelp # provides RELP syslog reception $InputRELPServerRun 20514 when I restart rsyslog I am told it does not like my InputRELPServerRun line: Oct 28 13:43:54 scan rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="7102" x-info="http://www.rsyslog.com"] start Oct 28 13:43:54 scan rsyslogd: the last error occured in /etc/rsyslog.conf, line 23:"$InputRELPServerRun 20514" Any clues?

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ZFS on Linux testing effort
by Andrew Holway 02 Mar '14

02 Mar '14

Hey, http://zfsonlinux.org/epel.html If you have a little time and resource please install and report back any problems you see. A filesystem or Volume sits within a zpool a zpool is made up of vdevs vdevs are made up of block devices. zpool is similar to LVM volume vdev is similar to raid set devices can be files. Thanks, Andrew

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died again
by Michael Hennebry 04 Feb '14

04 Feb '14

CentOS 6.4 died on me again. Didn't leave any traces that I could find. The screen just suddenly went black. Couldn't switch to another virtual terminal. Pushing the reset button worked. Didn't have to power off this time. -- Michael hennebry(a)web.cs.ndsu.NoDak.edu "On Monday, I'm gonna have to tell my kindergarten class, whom I teach not to run with scissors, that my fiance ran me through with a broadsword." -- Lily

21 145

idea: "hybrid" iso images?
by Joseph Spenner 30 Jan '14

30 Jan '14

In order to create a bootable CentOS installation USB thumb drive, there are several steps one must follow. The process often involves using a Windows box, which can be kinda annoying. The Linux Mint distro has what they call a "Hybrid" iso image. (see: http://community.linuxmint.com/tutorial/view/744 ) This image can be written to a thumb drive and used for installation simply by performing: # dd /path/to/image.iso of=/dev/sdb (where /dev/sdb is the thumb drive device). This thumb drive can now be booted and used for installation. The same image.iso file can be written to CD/DVD to create the installation media as well. Is this a complicated ISO build process? I'm frequently installing to systems without CD/DVD drives, so this would come in handy. Thanks! Regards, Joseph Spenner ______________________________________________________________________ If life gives you lemons, keep them-- because hey.. free lemons. "♥ Sticker" fixer: http://microflush.org/stuff/stickers/heartFix.html

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EPEL problem
by Phil Dobbin 26 Jan '14

26 Jan '14

Hi, all. I'm trying to install the EPEL repo on a fully up to date CentOS 6.4. I'm using wget to download from my usual source but after I install it via `sudo rpm -ivh epel-xxxxx` it's not actually there in `/etc/yum.repos.d`. Trying to install it again, Yum just tells me it's already installed. I've no idea where it is installed if it is (which I don't think it is) so I'm stumped. Any help appreciated. Cheers, Phil... -- currently (ab)using Arch Linux, CentOS 6.4, Debian Squeeze & Wheezy, Fedora 19 & 20, OS X Snow Leopard & Tiger, Ubuntu Quantal, Raring & Saucy GnuGPG Key : http://phildobbin.org/publickey.asc

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Discuss November 2013