Discuss March 2014

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167 participants
144 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,

5 7

RHEL7 beta discussions?
by Les Mikesell 08 May '14

08 May '14

Where would be an appropriate place to get help with the quirks of RHEL7 beta, particularly GUI usability issues? Gnome3 won't work under x2go, so I'm trying to use KDE but can't believe that anyone actually uses borderless windows where you can't tell where you are clicking near the edges, grey-background terminals or the default font set. So there must be some other themes or a lot that I don't know about it. -- Les Mikesell lesmikesell(a)gmail.com

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Does anyone use tcp wrappers (hosts.allow/hosts.deny) anymore?
by Matthew Miller 22 Apr '14

22 Apr '14

Does anyone use tcp wrappers (hosts.allow/hosts.deny) anymore? And, would you care strongly if it went away (or would you just migrate to something else)? I bring this up because we are discussing dropping it from Fedora. This would be far enough in the future that it wouldn't impact RHEL 7, and therefore won't affect anyone here for Quite Some Time*, but here in the new world order of CentOS, I thought it might be useful to check with some actual downstream users. What do you think? Do you rely on hosts.allow/hosts.deny a primary security mechanism? As defense-in-depth? Do you have policies which mandate it? Your feedback appreciated. Thanks! * and the standard caveats that Fedora doesn't necessarily determine the path for RHEL apply, of course. -- Matthew Miller mattdm(a)mattdm.org <http://mattdm.org/>

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Re: [CentOS] Motion Detecting Camera
by tdukes＠palmettoshopper.com 21 Apr '14

21 Apr '14

-------- Original Message -------- Subject: [CentOS] Motion Detecting Camera From: Leslie S Satenstein <lsatenstein(a)yahoo.com> Date: Sat, February 01, 2014 7:27 am To: "centos(a)centos.org" <centos(a)centos.org> mark wrote With the continuing annoyance from motion, my manager's asked me to go looking again for a video surveillance appliance: basically, a motion-detecting DVR and cameras. The big thing, of course, is a) price (this is a US federal gov't agency, and being civilian, money is *tight*, don't give me the libertarian/GOP line about how freely we spend, thankyouverymuch), b) it has to be on the network, and c) we need to be able to d/l to a server, and rm after we do that... and we want to script or cron job that. I was in Costco (USA warehouse store) and saw a Philips LED display, Camera, Recorder, that was motorized. The camera followed the movement across the front of it, and could snapshot to a memory chip. It was under $80.00 for the ensemble. The floor model worked well. If you do not require realtime recording to a hard disk, then this item may be a reasonable cost solution. Regards Leslie Mr. Leslie Satenstein SENT FROM MY OPEN SOURCE LINUX SYSTEM. _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.centos.org/mailman/listinfo/centos Checkout bluecherry.net

6 7

biosdevname
by Steve Clark 11 Apr '14

11 Apr '14

Hello, Anybody else run into problems with biosdevname .0.5..0-2 changing names from p2p1 to em1 when upgrading from biosdevname 0.4.1-3? Darn! I thought biosdevname was to keep the names the same!! -- Stephen Clark *NetWolves Managed Services, LLC.* Director of Technology Phone: 813-579-3200 Fax: 813-882-0209 Email: steve.clark(a)netwolves.com http://www.netwolves.com

6 13

cachefs
by Rita 10 Apr '14

10 Apr '14

has anyone been using cachefs with 6.x series? i have tried using it but i keep getting hung processes after 2 weeks. ATM, running 6.3 but was curious if its more stable on Centos 6.5? -- --- Get your facts first, then you can distort them as you please.--

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Discuss March 2014