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Disk array format for CentOS virtual host
by Chuck Munro 18 Dec '10

18 Dec '10

Hello List Members (and Holiday greetings!) This rambles a bit ... my apologies in advance. I am in the process of building a large CentOS-based VM host machine which will replace several individual boxes. I've done the usual hardware research and ended up with a SuperMicro motherboard, dual Xeons, lots of ECC RAM, solid power supply, and tons of cooling. When it comes to the best disk array layout for 7 guest instances of CentOS (mostly 64-bit) I run into the classical argument of disk I/O performance versus array robustness. I'm using Linux software RAID so I don't get locked into a vendor's controller, and because I've got CPU cycles to burn. The intent is to use CentOS-6 with KVM after climbing the usual experimental learning curve. I've got years of CentOS experience, but none with KVM. So, underneath all of this I could use RAID-10/RAID-6/RAID-60. Which one is better for the following work mix: - 4 web servers, not heavily loaded (yet), mostly CGI. - 2 independent Zimbra email servers, which seem to spend most of their time rejecting spam and malware. - A primarily-inbound FTP server with bandwidth throttling. - A batch ImageMagick video process which kicks in a couple of times/day for a few minutes. - A secondary/backup SMB server, not heavily used. - A very lightly loaded DDNS server. Two spindles will be used in RAID-1 for the host OS filesystems. I have 10 large drives for the guest machines, but because they're 2 TByte I want to ensure reasonable fault tolerance, meaning the ability to handle at least two drive failures. This really means that an array rebuild to replace *one* drive stands a good chance of succeeding. At first glance this would seem to be a system which will be doing more reads than writes, so RAID-6 or 60 might be a reasonable fit. RAID-10 offers much better write performance according to what I've been reading, but is less fault tolerant. RAID-60 is a bit of an unknown to me with regard to performance. In case you're wondering, I don't consider RAID to be a backup, so all of this will be automatically backed up to duplicate separate machines, each having tons of RAID-6 storage. Each individual guest OS will do its own rsync thing. Please forgive my lack of VM experience, but an additional question ... I'm thinking of creating a separate RAID-xx MD partition for each guest. Should I hand each over as a 'device' to KVM or is it better to place the guest filesystems in a big file on each separate MD partition? Or, is it better to create one huge RAID-xx partition and just use big filesystems-in-a-file. Either way would probably take the same amount of time (long!) to rebuild an array, if I understand this correctly. The collective wisdom of this list is most welcome. Thanks muchly, Chuck

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server version on laptop
by Johan Scheepers 18 Dec '10

18 Dec '10

Good day, What can I expect if I should install a server version of a distro on my laptop, please. Thanks Johan

6 7

cobbler fails to recognize semanage rules
by bluethundr 18 Dec '10

18 Dec '10

I am having a bit of trouble setting up cobbler on this machine. cobbler check points out a few things to correct: [root@VIRTCENT04:~]#cobbler check The following are potential configuration items that you may want to fix: 1 : you need to set some SELinux content rules to ensure cobbler serves content correctly in your SELinux environment, run the following: /usr/sbin/semanage fcontext -a -t public_content_t "/tftpboot/.*" && /usr/sbin/semanage fcontext -a -t public_content_t "/var/www/cobbler/images/.*" 2 : you need to set some SELinux rules if you want to use cobbler-web (an optional package), run the following: /usr/sbin/semanage fcontext -a -t httpd_sys_content_rw_t "/var/lib/cobbler/webui_sessions/.*" 3 : some network boot-loaders are missing from /var/lib/cobbler/loaders, you may run 'cobbler get-loaders' to download them, or, if you only want to handle x86/x86_64 netbooting, you may ensure that you have installed a *recent* version of the syslinux package installed and can ignore this message entirely. Files in this directory, should you want to support all architectures, should include pxelinux.0, menu.c32, elilo.efi, and yaboot. The 'cobbler get-loaders' command is the easiest way to resolve these requirements. 4 : since iptables may be running, ensure 69, 80, and 25151 are unblocked 5 : debmirror package is not installed, it will be required to manage debian deployments and repositories 6 : The default password used by the sample templates for newly installed machines (default_password_crypted in /etc/cobbler/settings) is still set to 'cobbler' and should be changed, try: "openssl passwd -1 -salt 'random-phrase-here' 'your-password-here'" to generate new one Restart cobblerd and then run 'cobbler sync' to apply changes. I try to apply the first suggestion: [root@VIRTCENT04:~]#/usr/sbin/semanage fcontext -a -t public_content_t "/tftpboot/.*" && /usr/sbin/semanage fcontext -a -t public_content_t "/var/www/cobbler/images/.*" /usr/sbin/semanage: File context for /tftpboot/.* already defined And the system points out that the rules are already defined by semanage. the cobbler service restarts: [root@VIRTCENT04:~]#service cobblerd restart Stopping cobbler daemon: [ OK ] Starting cobbler daemon: [ OK ] [root@VIRTCENT04:~]#SERVING! sync is fine [root@VIRTCENT04:~]#cobbler sync task started: 2010-12-18_105137_sync task started (id=Sync, time=Sat Dec 18 10:51:37 2010) running pre-sync triggers cleaning trees removing: /tftpboot/pxelinux.cfg/default removing: /tftpboot/s390x/profile_list copying bootloaders copying: /usr/lib/syslinux/pxelinux.0 -> /tftpboot/pxelinux.0 copying: /usr/lib/syslinux/menu.c32 -> /tftpboot/menu.c32 copying: /boot/memtest86+-1.65 -> /tftpboot/memtest86+-1.65 copying: /usr/lib/syslinux/memdisk -> /tftpboot/memdisk copying distros copying images generating PXE configuration files rendering Rsync files generating PXE menu structure running post-sync triggers *** TASK COMPLETE *** run cobbler check again: [root@VIRTCENT04:~]#cobbler check The following are potential configuration items that you may want to fix: 1 : you need to set some SELinux content rules to ensure cobbler serves content correctly in your SELinux environment, run the following: /usr/sbin/semanage fcontext -a -t public_content_t "/tftpboot/.*" && /usr/sbin/semanage fcontext -a -t public_content_t "/var/www/cobbler/images/.*" 2 : you need to set some SELinux rules if you want to use cobbler-web (an optional package), run the following: /usr/sbin/semanage fcontext -a -t httpd_sys_content_rw_t "/var/lib/cobbler/webui_sessions/.*" 3 : some network boot-loaders are missing from /var/lib/cobbler/loaders, you may run 'cobbler get-loaders' to download them, or, if you only want to handle x86/x86_64 netbooting, you may ensure that you have installed a *recent* version of the syslinux package installed and can ignore this message entirely. Files in this directory, should you want to support all architectures, should include pxelinux.0, menu.c32, elilo.efi, and yaboot. The 'cobbler get-loaders' command is the easiest way to resolve these requirements. 4 : since iptables may be running, ensure 69, 80, and 25151 are unblocked 5 : debmirror package is not installed, it will be required to manage debian deployments and repositories 6 : The default password used by the sample templates for newly installed machines (default_password_crypted in /etc/cobbler/settings) is still set to 'cobbler' and should be changed, try: "openssl passwd -1 -salt 'random-phrase-here' 'your-password-here'" to generate new one Restart cobblerd and then run 'cobbler sync' to apply changes. same thing... what can I do to get beyond this infinite loop? -- GPG me!! gpg --keyserver pgp.mit.edu --recv-keys F186197B

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centos 5.5 x86_64 mixing with i386 rpms
by Johan Scheepers 18 Dec '10

18 Dec '10

Good day, What will happen if on x86_64 some i386 rpms get installed, please. Thanks Johan

3 4

Re: [CentOS] Centos 5.5 - Kernel Panic while booting.
by Lisandro Grullon 18 Dec '10

18 Dec '10

Akemi, Why is the vault download like a snail, I usually download 2-3MB/s from the mirrors, but this one your provide only getting 12-15Kbps. Is there anything faster? >>> Akemi Yagi 12/17/10 8:13 PM >>> On Fri, Dec 17, 2010 at 5:11 PM, Lisandro Grullon wrote: > Akemi, > I went through the different mirrors and was unable to locate the ISO as it > is stated as deprecated or unsupported, is there any plans to fix this issue > in 5.6 or rather 6.x release. It appears that the latest build from Centos > was built back in may, lots of bugs have emerge since them including this > one relating to a kernel panic. Please advise in the location of 5.4, i am > willing to try it. It's here: http://vault.centos.org/5.4/ Akemi

2 1

Re: [CentOS] Centos 5.5 - Kernel Panic while booting.
by Lisandro Grullon 18 Dec '10

18 Dec '10

Akemi, I went through the different mirrors and was unable to locate the ISO as it is stated as deprecated or unsupported, is there any plans to fix this issue in 5.6 or rather 6.x release. It appears that the latest build from Centos was built back in may, lots of bugs have emerge since them including this one relating to a kernel panic. Please advise in the location of 5.4, i am willing to try it. >>> Akemi Yagi 12/17/10 7:56 PM >>> On Fri, Dec 17, 2010 at 4:26 PM, Lisandro Grullon wrote: > Tru, looks like a bug in centos, I just loaded RHEL 6 without any issues. I > dont think it has something to do with the actual image file, but in any > case maybe I should re-download the entire DVD again just to make sure. > Thank you Tru. > >>>> Tru Huynh 12/17/10 6:47 PM >>> > maybe you are hitting: http://bugs.centos.org/view.php?id=4581 > > Tru This is not a CentOS bug. As stated in the KB articles quoted in the bug report: https://access.redhat.com/kb/docs/DOC-31516 https://access.redhat.com/kb/docs/DOC-38013 the patch is in the kernel-2.6.18-194.3.1 and onward. CentOS/RHEL 5.5 comes with kernel-2.6.18-194 which has the bug. RHEL-6's kernel is much newer at 2.6.32-71, so it does not have this bug. Therefore to get around this issue, as suggested in one of the KB articles, you first install CentOS *5.4* and then update it to the current kernel thus skipping the problematic kernel. Akemi _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.centos.org/mailman/listinfo/centos

2 1

Re: [CentOS] Centos 5.5 - Kernel Panic while booting.
by Lisandro Grullon 18 Dec '10

18 Dec '10

Tru, looks like a bug in centos, I just loaded RHEL 6 without any issues. I dont think it has something to do with the actual image file, but in any case maybe I should re-download the entire DVD again just to make sure. Thank you Tru. >>> Tru Huynh 12/17/10 6:47 PM >>> On Fri, Dec 17, 2010 at 06:23:52PM -0500, Lisandro Grullon wrote: > Dear centos community, > I was in the process of loading the latest 5.5 release of centos in a VMWARE ESX 4.1 host as my first virtual machine, suddenly while booting I got a panic error with the following on screen. Can someone point me in the right direction. This machine has 24 cores and I allocated 1 for Centos to use with 1024MB of memory. Any clues or workaround to solve this problem? Thank you in advance. maybe you are hitting: http://bugs.centos.org/view.php?id=4581 Tru -- Tru Huynh (mirrors, CentOS i386/x86_64 Package Maintenance) http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xBEFA581B

2 1

Re: [CentOS] Centos 5.5 - Kernel Panic while booting.
by Lisandro Grullon 17 Dec '10

17 Dec '10

Tru, you nailed it right. I will load Ubuntu and Debian and will report back, this may be a bug in the loading process. I did install this system with Centos by itself and it load ok, but the virtual machine its not loading and it just keep crashing with the same error as the bug you provided/posted. Maybe someone can shine some light on this. Thank you. >>> Tru Huynh 12/17/10 6:47 PM >>> On Fri, Dec 17, 2010 at 06:23:52PM -0500, Lisandro Grullon wrote: > Dear centos community, > I was in the process of loading the latest 5.5 release of centos in a VMWARE ESX 4.1 host as my first virtual machine, suddenly while booting I got a panic error with the following on screen. Can someone point me in the right direction. This machine has 24 cores and I allocated 1 for Centos to use with 1024MB of memory. Any clues or workaround to solve this problem? Thank you in advance. maybe you are hitting: http://bugs.centos.org/view.php?id=4581 Tru -- Tru Huynh (mirrors, CentOS i386/x86_64 Package Maintenance) http://pgp.mit.edu:11371/pks/lookup?op=get&search=0xBEFA581B

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Centos 5.5 - Kernel Panic while booting.
by Lisandro Grullon 17 Dec '10

17 Dec '10

Dear centos community, I was in the process of loading the latest 5.5 release of centos in a VMWARE ESX 4.1 host as my first virtual machine, suddenly while booting I got a panic error with the following on screen. Can someone point me in the right direction. This machine has 24 cores and I allocated 1 for Centos to use with 1024MB of memory. Any clues or workaround to solve this problem? Thank you in advance. Unable to handle kernel NULL pointer dereference at 0000000000000040 RIP: [] cpuid4_cache_lookup+0x256/0x356 PGD 0 Oops: 0000 [1] SMP last sysfs file: CPU 0 Modules linked in: Pid: 1, comm: swapper Not tainted 2.6.18-194.el5 #1 RIP: 0010:[] [] cpuid4_cache_lookup+0x256/6 RSP: 0000:ffff81010fc75d60 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000060 RCX: 00000000000006aa RDX: 0000000000000000 RSI: 0000000000000060 RDI: 0000000000000003 RBP: ffff81010f765580 R08: 0000000000000001 R09: 0000000000000040 R10: ffff81010fc75cf0 R11: 0000000000000060 R12: 0000000000000080 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffffffff803cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b CR2: 0000000000000040 CR3: 0000000000201000 CR4: 00000000000006e0 Process swapper (pid: 1, threadinfo ffff81010fc74000, task ffff81010fc657a0) Stack: ffff81010fc75e00 000280000f765ec0 0000000000000000 0000000000000000 0000000040020140 00000000000000d0 ffff810140020140 0000000000000286 00000000000006a9 0000000000000000 0000000017c0003f 0000000000000000 Call Trace: [] cacheinfo_cpu_callback+0xe9/0x516 [] cacheinfo_cpu_callback+0x134/0x516 [] cache_sysfs_init+0x39/0x54 [] init+0x1f9/0x2f7 [] child_rip+0xa/0x11 [] acpi_ds_init_one_object+0x0/0x80 [] init+0x0/0x2f7 [] child_rip+0x0/0x11 Code: 8b 72 40 48 8d 4c 24 1c 48 8b 7a 20 ba c4 01 00 00 e8 5f 77 RIP [] cpuid4_cache_lookup+0x256/0x356 RSP CR2: 0000000000000040 <0>Kernel panic - not syncing: Fatal exception

3 2

Re: [CentOS] CentOS 5.5 Sofware RAID1
by Lisandro Grullon 17 Dec '10

17 Dec '10

When you boot does the OS see both drives, if so, why not configure using LVM. >>> Matt 12/17/10 6:29 PM >>> I have the CentOS 5.5 install DVD and trying to install with software RAID1 on two 2TB SATA drives. The CentOS install only sees one drive. This is a Supermicro motherboard with fakeraid turned off in bios. I tried the trick like so: dd if=/dev/zero of=/dev/sda bs=512 count=64 dd if=/dev/zero of=/dev/sdb bs=512 count=64 Still no go. linux rescue console does see both sda and sdb. Whats going on? _______________________________________________ CentOS mailing list CentOS(a)centos.org http://lists.centos.org/mailman/listinfo/centos

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