Discuss December 2015

discuss@lists.centos.org

131 participants
134 discussions

SSD for Centos SWAP /tmp & /var/ partition
by Keith Roberts 03 Sep '25

03 Sep '25

Has anyone actually used a SSD in a Centos setup? My little experiment with a s/h WD drive for /tmp and SWAP partitions kicked the bucket on Wednesday, when the poor WD drive caught the click-of-death. It was a s/h drive to start with and lasted about 4 months. But that was without the /var/log/ partition being written to it, as I mounted that back onto /var/log from the original drive. So I had to install another (WD) drive, and repartion it and rebuild my RPM package database, from the backed-up Packages file. That seems to be all OK now. I'm wondering if it would be a good idea to use a new SSD for moving all the disk i/o to, that Linux likes to do so often. Plus putting SWAP onto a decent SSD should speed things up somewhat. Here's a short video of a laptop fitted with a SSD drive booting macOS, compared to a similar laptop booting from the standard HDD. The laptop with the SSD boots and loads some apps in 28 seconds. The other one takes twice as long. http://eshop.macsales.com/shop/SSD/OWC/Mercury_Extreme_Pro_6G/?utm_source=t… Kind Regards, Keith Roberts ----------------------------------------------------------------- Websites: http://www.karsites.net http://www.php-debuggers.net http://www.raised-from-the-dead.org.uk All email addresses are challenge-response protected with TMDA [http://tmda.net] -----------------------------------------------------------------

33 96

I want to connect to a l2tp server from centos.
by Eliezer Croitoru 22 Mar '17

22 Mar '17

I have a server currently connecting to a pptp remote server. This server(lns\lac) has the option for pptp connections and l2tp connections. The l2tp connections are not using ipsec encryption at all. I have seen couple guides\tutorials on the internet: - https://raymii.org/s/tutorials/IPSEC_L2TP_vpn_on_CentOS_-_Red_Hat_Enterpris… - https://wiki.archlinux.org/index.php/L2TP/IPsec_VPN_client_setup But all the guides that I have found are using ipsec with "secret". On ubuntu there is a gui applet that helps setting these kind of connections up but I am working with a CentOS server and not Ubuntu desktop. If someone used l2tp the same way I want to use on CentOS 7 please give me some advice. If you have a guide which might help me I will be more then happy to see this one. Thanks, Eliezer

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Broadcom BCM4313 support broken with kernel 2.6.32-573.7.1.el6.centos.plus.x86_64?
by wwp 24 Aug '16

24 Aug '16

Hello, I noticed that with latest kernel (2.6.32-573.7.1.el6.centos.plus.x86_64), my laptop's Wifi doesn't work, whereas with previous kernel (2.6.32-504.30.3.el6.centos.plus.x86_64), it works fine. Is this a known issue or did I miss something new? BTW, `lspci` says: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter (rev 01) Regards, -- wwp

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Any further developments on CentOS7 for i386?
by Kay Schenk 22 Jun '16

22 Jun '16

Well I haven't tested out the CentOS 7 for i386 yet as sent in the message of 06/02-- https://lists.centos.org/pipermail/centos-devel/2015-June/013426.html Nor have I seen any additional information. So how is this going? I'm almost ready to jump in as I would really prefer to be on Gnome 3. -- -------------------------------------------- MzK “The journey of a thousand miles begins with a single step.” --Lao Tzu

3 7

abrt-watch-log -F BUG: WARNING: at WARNING: CPU: INFO: possible recursive locking detected
by Michael H 15 Feb '16

15 Feb '16

Hi All, I've been tuning a server recently and just today this has started to appear in my top/htop output. [root@db1 ~]# ps -aux | grep kernel root 1011 0.0 0.0 212048 4532 ? Ss 13:34 0:00 /usr/bin/abrt-watch-log -F BUG: WARNING: at WARNING: CPU: INFO: possible recursive locking detected ernel BUG at list_del corruption list_add corruption do_IRQ: stack overflow: ear stack overflow (cur: eneral protection fault nable to handle kernel ouble fault: RTNL: assertion failed eek! page_mapcount(page) went negative! adness at NETDEV WATCHDOG ysctl table check failed : nobody cared IRQ handler type mismatch Machine Check Exception: Machine check events logged divide error: bounds: coprocessor segment overrun: invalid TSS: segment not present: invalid opcode: alignment check: stack segment: fpu exception: simd exception: iret exception: /var/log/messages -- /usr/bin/abrt-dump-oops -xtD I had made a few changes to sysctl.conf which I have now reverted and the error still exists. my sysctl.conf contained; vm.swappiness=0 vm.overcommit_memory=2 vm.overcommit_ratio=90 - this was only added this morning because of an 'out of memory' error in postgresql. kernel.shmmax=35433480192 kernel.shmall=2214592512 which I have now removed. Can anyone shine any light on this? A little search on Google mentions faulty memory, I will install memtest today and see what the output is like. Thanks Michael

2 1

Folding At Home
by Mark LaPierre 02 Feb '16

02 Feb '16

Hey Y'all, I have the Stanford University Folding At Home project running on three of my machines. I had them all set up so that I could control them all from my main machine, 192.168.15.101, but some time ago something changed so that I can no longer connect to the FAH clients on the other two machines. I figured it wasn't really important so I would look into it later. Well time has passed and my Christmas break is almost passed too to I guess this is the time to figure it out. I can still SSH onto both machines. I can ping both machines. When I open the FAH Control on my machine connection to clients running on 192.168.15.105 and 192.168.15.107 fails. I'm assuming that there would be an entry in a log on those two machines detailing the failed connection attempt. What log file should I be looking at? -- _ °v° /(_)\ ^ ^ Mark LaPierre Registered Linux user No #267004 https://linuxcounter.net/ ****

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Centos 7 guest - long delay on mounting /boot with host disk write cache off
by Andrzej Szymanski 12 Jan '16

12 Jan '16

Hello, I've noticed a strange delay while booting a CentOS 7 guest on a CentOS 7 host with slow disks (7200RPM) with write cache off. The guest and host are freshly installed Centos 7 (host was fully patched before guest install). Guest is installed on an lvm pool residing on an md raid1 with two SATA 7200 RPM drives with their write caches off. The delay is on mounting /boot, the dmesg on the guest says: [ 23.491857] XFS (vda1): Mounting V4 Filesystem [ 46.668396] XFS (vda1): Ending clean mount [ 46.668404] SELinux: initialized (dev vda1, type xfs), uses xattr Subsequent mounts by hand on a running system last even longer - dmesg records: [ 96.442544] XFS (vda1): Unmounting Filesystem [ 100.086741] XFS (vda1): Mounting V4 Filesystem [ 146.098703] XFS (vda1): Ending clean mount [ 146.098721] SELinux: initialized (dev vda1, type xfs), uses xattr mounting "-o ro" doesn't help - dmesg records: [ 205.552778] XFS (vda1): Unmounting Filesystem [ 212.452724] XFS (vda1): Mounting V4 Filesystem [ 258.537459] XFS (vda1): Ending clean mount [ 258.537477] SELinux: initialized (dev vda1, type xfs), uses xattr but mounting with "-o ro,norecovery" does help - dmesg records: [ 263.795813] XFS (vda1): Unmounting Filesystem [ 271.973701] XFS (vda1): Mounting V4 filesystem in no-recovery mode. Filesystem will be inconsistent. [ 272.003618] SELinux: initialized (dev vda1, type xfs), uses xattr xfs_logprint -t /dev/vda1 says that the device is clean: xfs_logprint: data device: 0xfc01 log device: 0xfc01 daddr: 512032 length: 6824 log tail: 3447 head: 3447 state: <CLEAN> however the full xfs log contains a lot of entries xfs_logprint /dev/vda1 results in ~23000 lines of text. Permanent help is from xfs_repair which zeroes the log - a subsequent mount is fast, and subsequent reboots are fast. [ 411.290031] XFS (vda1): Mounting V4 Filesystem [ 411.456661] XFS (vda1): Ending clean mount [ 411.456676] SELinux: initialized (dev vda1, type xfs), uses xattr During the problematic mounts the host reports a lot of small disk writes with queue depth ~1. Also, when I move the problematic filesystem using dd to an lvm volume, mount -o ro, unmount, make snapshot, mount -o ro again, then the contents of the original volume are the same as the snapshot but the snapshot usage increases from 0 to ~2MB - so something writes to the original volume in a ro mode - possibly a log replay. Is is normal for the xfs mount to replay a log after a clean unmount? With best regards, Andrzej -- Andrzej Szymański, Ph.D. tel. +48 12 6174035 fax. +48 12 6342372 e-mail: szymans(a)agh.edu.pl AGH University of Science and Technology Department of Telecommunications Al. Mickiewicza 30 30-059 Kraków POLAND

2 2

Yum Weird Message
by Alice Wonder 08 Jan '16

08 Jan '16

I ran into this exact issue last night - http://www.iotti.biz/?p=433 When a computer is connected via IPv4 but the IPv4 a repo host connects to is not available, yum then tries the IPv6 address and will fail with a confusing message telling you it failed to connect to the IPv6 address. I don't know if there is a way for yum to figure out whether the current network connection to the Internet is IPv4 or IPv6. But if there is a way, it might make a usability improvement. A lot of people have no idea what IPv6 is and would be confused. I was confused myself at first, wondering if DHCP pulled in IPv6 from the router. -- -=- Sent my from my laptop, may not be able to respond timely

4 7

Extending a CentOS disk without reboot
by Sander Kuusemets 07 Jan '16

07 Jan '16

Hello, Today a virtual server under my administration ran out of disk space, so I had to get extra space to it.. while it was running, because it's an important web server without any kind of HA/Load Balancing (don't do that, kids). So what happened, is that after another administrator had extended the disk from VMWare, I tried to extend it from the OS side. Everything went well, listing my steps here: * echo 1 > /sys/class/scsi_device/2\:0\:0\:0/device/rescan * fdisk /dev/sdb (the usual, delete partition and make a new, bigger one) Now's when the problems happened. After writing the partition table I got the usual "Busy" error. But I needed to do this without downtime. So, what did I try to get the kernel acknowledge the partition size change: * hdparm -z /dev/sdb * partx -a -v /dev/sdb * partprobe -s * echo "1" > /sys/block/sdb/device/rescan And while dmesg reported that it recognized the partition change, LVM did still not see it. So eventually, I was still forced to reboot, after which everything (pvresize, lvresize, resize2fs) worked fine. Environment: * A VMWare virtual machine * CentOS 6.7 (Final) Is there any other way I'm missing? Is this caused by the fact that I was trying to resize a partition that is under the root file system? If so, then is it really impossible to do it live? Thanks, -- Sander Kuusemets University of Tartu, High Performance Computing, IT Specialist

4 5

systemd-sysctl not running on boot
by Ofer Hasson 06 Jan '16

06 Jan '16

Hey all, After upgrading to CentOS 7.2, non of my servers run systemd-sysctl on boot. So far, I tried running manually /usr/lib/systemd/systemd-sysctl, it runs smoothly and updates all the parameters. I also ran sysctl --system, which also executes successfully. I checked within systemd, and systemd-sysctl is wanted by the sysinit.target which is wanted by the multi-user.target - the one I boot into. I can't find anything by doing journalctl | grep sysctl Or by looking through /var/log/messages (I run rsyslog as well). Any idea's ? Thanks

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Discuss December 2015