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CentOS 6 docs?
by m.roth＠5-cent.us 07 Nov '12

07 Nov '12

Is there somewhere else than <http://www.centos.org/docs/> for documentation for CentOS 6? mark

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LVM question during an upgrade
by m.roth＠5-cent.us 07 Nov '12

07 Nov '12

Well, I'm upgrading a server from 5.8 to 6.3. Problem: someone built the system with LVM. I see some few differences between /etc/lvm/lvm.conf and the one from 6.3, and I'm trying to figure out what I can leave alone, and what I need to set to that from the old version. For example, the old one has preferred_names = [], and the new has a list. Anyone have thoughts about whether I can just copy over the old? I do know there are some new parameters (thin_*): do I need to add them? mark

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Install CentOS 6.3 to partitionable mdadm array
by Hal Martin 07 Nov '12

07 Nov '12

Hello all, I'm trying to install CentOS 6.3 to an mdadm partitionable array and not having any luck. The installer only allows me to create one file system per md device, or specify the md device as a LVM physical volume. I don't want to do either, I want to create one md device and create multiple partitions on top of the md device. I thought that perhaps the installer was preventing me from doing this because it wasn't possible to boot off a partitionable mdadm array, but through googling I don't believe this is the case. (See links at the bottom of this email) I've tried the graphical installer and the text-mode installer, and neither gives me the ability to install to a partitionable mdadm array. Even more annoying is that if I manually create such an array, partition it and create file systems, the installer will stop the array when starting the partitioning utility, preventing me from installing to the partitions I created. Is there an advanced mode in the installer that I can force it to install to a partitionable md device, or is that not an option? I'd like to avoid having multiple md devices on the same physical drives, and unfortunately the application I'm installing doesn't place nicely with LVM. Thanks, Hal http://www.kernel.org/doc/Documentation/md.txt http://www.miquels.cistron.nl/raid/ https://bugzilla.redhat.com/show_bug.cgi?id=447818

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CentOS-announce Digest, Vol 93, Issue 4
by centos-announce-request＠centos.org 07 Nov '12

07 Nov '12

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apcupsd
by m.roth＠5-cent.us 07 Nov '12

07 Nov '12

Anyone else around using apcupsd? I seem to be seeing a problem, and I'd like someone to check me on it: I edit /etc/apcupsd/apccontrol to replace the value of SHUTDOWN from /sbin/shutdown to /bin/false (we don't want 3 or 6 servers shutting down over a 2 second or so blip, which it really wants to do). What's happened is that a machine shut down the other day, and looking at it, I found that the config file was set to the original code... and I *KNOW*, for a fact, that I went through every single server that's attached to a UPS many months ago, after something important shut down, and fixed all of them. So, it looks like an upgrade undid my change, rather than creating apccontrol.rpmnew. Has anyone seen this behavior? mark

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tcsh
by Hossein Lanjanian 06 Nov '12

06 Nov '12

Hi every body for run a software on centos, I must use tcsh shell. but when I run the command: [root@localhost ~]# tcsh the following message appears: Bad : modifier in $ (/). please help! -- With The Best H.Lanjanian

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CentOS-announce Digest, Vol 93, Issue 3
by centos-announce-request＠centos.org 06 Nov '12

06 Nov '12

Send CentOS-announce mailing list submissions to centos-announce(a)centos.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.centos.org/mailman/listinfo/centos-announce or, via email, send a message with subject or body 'help' to centos-announce-request(a)centos.org You can reach the person managing the list at centos-announce-owner(a)centos.org When replying, please edit your Subject line so it is more specific than "Re: Contents of CentOS-announce digest..." Today's Topics: 1. CEBA-2012:1427 CentOS 6 util-linux-ng Update (Johnny Hughes) 2. CentOS Test Day, Friday Nov 9th 2012 (Karanbir Singh) ---------------------------------------------------------------------- Message: 1 Date: Mon, 5 Nov 2012 15:41:09 +0000 From: Johnny Hughes <johnny(a)centos.org> Subject: [CentOS-announce] CEBA-2012:1427 CentOS 6 util-linux-ng Update To: centos-announce(a)centos.org Message-ID: <20121105154109.GA7043(a)chakra.karan.org> Content-Type: text/plain; charset=us-ascii CentOS Errata and Bugfix Advisory 2012:1427 Upstream details at : https://rhn.redhat.com/errata/RHBA-2012-1427.html The following updated files have been uploaded and are currently syncing to the mirrors: ( sha256sum Filename ) i386: dd7a5fd8bb775e27e343865d7a9110946382b1f49e295ba90ea84331fd7636f3 libblkid-2.17.2-12.7.el6_3.i686.rpm b4005a1bc774bd66cc05df7cf364805efc109a28f1829c267e586611a43b5872 libblkid-devel-2.17.2-12.7.el6_3.i686.rpm 8424b15885f76f63f13aadc33c4c0272ea6d00a95495845fcfc3e3716030e603 libuuid-2.17.2-12.7.el6_3.i686.rpm be69f072ff0e0117b91c2935828b256456fdf3418dd518b6191a01abd3e27b66 libuuid-devel-2.17.2-12.7.el6_3.i686.rpm 877c38619713a86c631d0c2fa1b1d216a502a0df228a05dcd6aaad1bd797102c util-linux-ng-2.17.2-12.7.el6_3.i686.rpm d793420f8c03d1cc98ee797527e3f989151fd4c683d67d71fb57503db20e9fda uuidd-2.17.2-12.7.el6_3.i686.rpm x86_64: dd7a5fd8bb775e27e343865d7a9110946382b1f49e295ba90ea84331fd7636f3 libblkid-2.17.2-12.7.el6_3.i686.rpm c0d1052c15e5a797e5b24096cab075c781aa4403f440fff1537f644384dc4479 libblkid-2.17.2-12.7.el6_3.x86_64.rpm b4005a1bc774bd66cc05df7cf364805efc109a28f1829c267e586611a43b5872 libblkid-devel-2.17.2-12.7.el6_3.i686.rpm 33ce2412f436c434efd3515f135ea546207faa83ec4db162ff7d662dd0cb08d8 libblkid-devel-2.17.2-12.7.el6_3.x86_64.rpm 8424b15885f76f63f13aadc33c4c0272ea6d00a95495845fcfc3e3716030e603 libuuid-2.17.2-12.7.el6_3.i686.rpm 3596829dcc1d5f16406e69244c1741232516d336ff43354b2d2c169fae2813d5 libuuid-2.17.2-12.7.el6_3.x86_64.rpm be69f072ff0e0117b91c2935828b256456fdf3418dd518b6191a01abd3e27b66 libuuid-devel-2.17.2-12.7.el6_3.i686.rpm 7b1a7796f8afcf4c2661c2c7c53fd7e16ec271aa63d17953fd36f2e34b1f4bab libuuid-devel-2.17.2-12.7.el6_3.x86_64.rpm 877c38619713a86c631d0c2fa1b1d216a502a0df228a05dcd6aaad1bd797102c util-linux-ng-2.17.2-12.7.el6_3.i686.rpm 39dda2f005352375f5d12c4064f117d3ef6dbd1b78a5ebe78418e513a144864f util-linux-ng-2.17.2-12.7.el6_3.x86_64.rpm 37bac3fd81a48610cf9df51f04ed1c48f0a4679e693ac5ba503a057a801c54ab uuidd-2.17.2-12.7.el6_3.x86_64.rpm Source: b11e72d9796cb0841aef84af8fb8bbadafd1902592be195254f153582e25635a util-linux-ng-2.17.2-12.7.el6_3.src.rpm -- Johnny Hughes CentOS Project { http://www.centos.org/ } irc: hughesjr, #centos(a)irc.freenode.net ------------------------------ Message: 2 Date: Mon, 05 Nov 2012 18:20:19 +0000 From: Karanbir Singh <kbsingh(a)centos.org> Subject: [CentOS-announce] CentOS Test Day, Friday Nov 9th 2012 To: CentOS Announcements List <centos-announce(a)centos.org> Message-ID: <50980363.4010709(a)centos.org> Content-Type: text/plain; charset=ISO-8859-1 Reminder Date: Friday November 9th, 2012 Time: From 5:00 UTC to 23:00 UTC We would like to invite everyone to come join us in #centos-devel on irc.freenode.net this Friday Nov 9th, 2012 for a CentOS test day. The aim of the exercise is to get more people looking at the tests we already have, running them on their infrastructure and ultimately joining the effort as contributors. You will need a machine instance ( either physical machine, or a VPS or a Cloud Instance or a VM on your machine ); need a VM image ? you can download one from here as prep : http://dev.centos.org/centos/test-images/ - being able to connect to the internet from that machine instance is essential, and as there are quite a few packages installed / uninstalled / cleaned out - a local CentOS mirror would be handy if you are on a slow link to the internet. The tests are mostly written in bash, but you can use any language you like - just grab yourself a gitorious.org account in advance. Knowledge of git helps, but isn't necessary. The test day will run from 05:00 UTC till 23:00 UTC, and there will be a couple of the CentOS QA guys and people who have contributed to the tests already, to help you get started and join the effort. We will have brief, clear instructions on : - Getting a copy of the most current tests - Set them up on your machine instance - Run the tests - Feedback results and recommendations - Templates to write new tests with - Submission process to contribute new tests - Instructions on howto run the tests regularly in the future The Test Day landing page is being setup here : http://wiki.centos.org/QaWiki/TestDay and will be ready by Wednesday Nov 7th, 2012. These tests are important : we run then every time there is a new iso, new image, new updates etc ready to be released by the project. Getting good and widespread coverage of these tests means that we all end up getting more trustworthy updates. See you then! -- Karanbir Singh, The CentOS Project +44-207-0999389 | http://www.centos.org/ | twitter.com/CentOS GnuPG Key : http://www.karan.org/publickey.asc ------------------------------ _______________________________________________ CentOS-announce mailing list CentOS-announce(a)centos.org http://lists.centos.org/mailman/listinfo/centos-announce End of CentOS-announce Digest, Vol 93, Issue 3 **********************************************

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Copying a file to a usb stick
by Twanny Azzopardi 06 Nov '12

06 Nov '12

Hello list, I formatted a 64MB usb stick with this command 'mkfs.ext2 -b 1024 /dev/XXX1' , to copy a file of 9230653440, but when it reached 7921295360, it gave input/ output error and the file is not copied. How should this be done?

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Re: [CentOS] Problem with CLVM (really openais)
by Digimer 05 Nov '12

05 Nov '12

On 11/05/2012 02:04 PM, Cris Rhea wrote: > On Sun, Nov 04, 2012 at 11:59:08AM -0500, Digimer wrote: >> On 11/04/2012 10:48 AM, Cris Rhea wrote: >>> One of the nodes will be barking about trying to fence the "failed" node >>> (expected, as I don't have real fencing). >> >> This is your problem. Without fencing, DLM (which is required for >> clustered LVM, GFS2 and rgmanager) is designed to block when a fence is >> called and stay blocked until the fence succeeds. Why it was called is >> secondary, even if a human calls the fence and everything is otherwise >> working fine, the cluster will hang. >> >> This is by design. "A hung cluster is better than a corrupt cluster". > > I understand what you're saying, but I've got three concerns: > > 1. Yes, I believe DLM is acting appropriately. It does "hang everything" > until fencing succeeds. If I manually fence the node (fence_ack_manual), > the remaining 3 nodes are fine. > > 2. As a practical matter, I cannot enable real fencing at this point. > These nodes are running VMs that are doing real stuff. Fencing a "failed > node" would dump the VMs. While I understand doing that in a real > failure situation, I have no indications that anyting is wrong (other than > aisexec/TOTEM issues). > > 3. At this point, this is NOT an HA cluster-- so I don't have VMs defined > as resources that need to be running someplace. All I'm tring to achieve > is to use CLVM (reliably) across a set of nodes. As far as the cluster is concerned, it is HA. The cluster does not understand the concept of unimportant things; It treats everything as critical. If you need CLVM (or anything else related to the cluster), then either make the VMs HA resources or move them off. Until you use real fencing, you will have problems. That said, some won't appear until it's too late if you try to avoid this. In short; use real fencing, period. Nothing else is supported or safe. >>> 4. OK, now reboot the "failed" node. It reboots and rejoins the cluster. >>> CLVM commands work, but are slow. Lots of these errors: >>> openais[7154]: [TOTEM] Retransmit List: fe ff >> >> Only time I've seen this happen is when something starves a node (slow >> network, loaded cpu, insufficient ram...). > > What methods would you use to pin this down? From my perspective, the > machines have enough RAM (large blades with fairly small VMs), decent CPU > (I can be logged into the node via SSH while this is happening and don't > see a performance issue), and no network "glitches" (the aisexec failure > happens well after machine has booted and come on-line on the network). This requires the assistance of the devs/advanced support people. If you have Red Hat support, please call them. >>> 5. This goes on for about 10 minutes and the whole cycle repeats (one of >>> the other nodes will "fail"...) >> >> If a totem packet fails to return from a node within a set period of >> time more than a set number of times in a row, the node is declared lost >> and a fence action is initiated. > > Yup, got that. How can I debug this further? I have no indication (other > than aisexec) that anything is wrong. Same as above comment. >>> 1. Switches have IGMP snooping disabled. This is a simple config, so >>> no switch-to-switch multicast is needed (all cluster/multicast traffic >>> stays on the blade enclosure switch). I've had the cluster >>> messages use the front-end net and the back-end net (different switch >>> model)-- no change in behavior. >> >> Are the multicast groups static? Is STP disabled? > > I'm not a cisco command guru (so please provide real commands in any hints). Nor am I. Whenever I hear "cisco", it's along with problems cause by Cisco doing non-standard things. > I have not defined anything in the switch for MC groups. In speaking with > my local network team, turning off IGMP snooping should allow full/unlimited > MC within that switch. Again, only a single switch involved, so no > switch-switch configs needed for MC. As I understand it, Cisco periodically purges multicast groups, forcing machine to resubscribe, as a way to clean out disused groups. This breaks the cluster comms. This is just one example of what might be happening. The take-away is that latency must remain below 2ms and multicast messages must never be interrupted. Your network people should be able to interpret that further. > Do I need to do something else within the switch or cluster configs to > aid MC? All the nodes are using the default MC address/port. Set a static multicast group, for one. > STP is currently enabled (set to pvst). This can cause problems. When STP tries to find loops, it can block a port or ports. This can break the cluster as well. Disable switch-wide STP and only enable it on outword-facing ports (if any at all). >>> 3. Tested multicast by enabling multicast/ICMP and running multicast >>> pings. Ran with no data loss for > 10 minutes. (IBM Tech web site >>> article-- where the end of the article say it's almost always a network >>> problem.) >> >> I'm leaning to a network problem, too. > > What else would you use to pinpoint the problem? A Dell M6220 switch > seems to be a Cisco clone, so any config suggestions are welcome. Again, I am not a cisco user. Ask your network engineer(s) and/or Red Hat for help specific to your environment. >> I don't think RRP worked in EL5... Maybe it does now? > > Good to know. As of 5.8, RRP doesn't seem to work for me (kernel faults). > >> First and foremost; Get fencing working. At the very least, a lost node >> will reboot and the cluster will recover as designed. It's amazing how >> many problems "just go away" once fencing is properly configured. Please >> read this: >> >> https://alteeve.com/w/2-Node_Red_Hat_KVM_Cluster_Tutorial#Concept.3B_Fencing > > Sure... makes perfect sense if one has REAL node failures. In my case, all > I'd have is a set of VMs crash (due to fencing) every 10 mins. The people > using those VMs wouldn't be very happy with me.... :) No, it makes sense whenever a node loses connection. The goal of fencing is to ensure that two nodes don't try to both provide HA services. If they can't talk to each other, then the *only* way to ensure that a node is the only one providing services is to fence the lost node. It does not matter at all that the rest of the machine is otherwise healthy. > (I've done AIX and HP HA clusters before, so I understand the need/purpose > for fencing failed nodes. In this case, I have real users using the VMs > on the nodes-- the only thing that appears to fail is aisexec's communication.) Then put your VMs under HA control. If the host node is lost, it will restart on a healthy node. It's the *only* safe option. -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?

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bind vs nfs
by Leon Fauster 05 Nov '12

05 Nov '12

Hi all, i have the situation where i need to have a nfs share on different locations on the client filesystem e. g. /vhost/one/htdocs/media /vhost/two/htdocs/media /vhost/.../htdocs/media is there some "performance" differences between mounting "media" every time via nfs or mount "media" only once via nfs and then remount "media" every time i need via "bind" locally? Just thinking/planing this right now. -- LF

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