systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
list-units [PATTERN...] List loaded units
BootModuleConfig.sh echo host-ind nfcd ........
You can search for this bug and it seems like it may be related to ecryptfs and is many years old.
The symptoms are that you return to the computer and the screensaver was active or the screen was asleep/black and it doesn't seem to come back. But you check by SSH the computer is running fine and are frustrated you'll lose your running programs and have to reboot.
There is a simple solution:
Ctrl + Alt + F1
Ctrl + Alt + F8
nfs mount failed:
mount 10.10.2.20:/tmp/nfsmount /mnt/nfs/
mount: wrong fs type, bad option, bad superblock on 10.10.2.20:/tmp/nfsmount,
missing codepage or helper program, or other error
(for several filesystems (e.g. nfs, cifs) you might
need a /sbin/mount.<type> helper program)
It looks like this has something to do with APIC but I am not sure. I have similar CPUs with a different MB and BIOS that work fine on the same type of kernel. A lot of time the issue is because of the C-step setting in the BIOS.
The same thing happened on the 2.6 kernel with Centos 6 but this is a homebrew 4.4 kernel so I am not sure why it is happening when even Centos 7 (3.2) kernel works OK.
Solution - It comes down to the BIOS set........
Error: Unable to apply new quota values: quota not running
Container start failed (try to check kernel messages, e.g. "dmesg | tail")
Killing container ...
Container was stopped
Error: Unable to apply new quota values: quota not running
Can't umount /vz/private/123123: Invalid argument
[root@rtt 123123]# vzquota on 123123
vzquota : (error) Can't open quota file for id 123123, maybe you need to reinit........
This container won't start after exhausting its memory. There are no relevant or helpful messages in dmesg or vzctl.log as well. Standard troubleshooting such as disabling PPP etc has not helped.
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Locked by: pid 166029, cmdline vzctl start 888171
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container already locked
2017-07-06T23:33:29-0400 vzctl : CT 888171 : Container was stopped
The only solution after trying many suggestions was to simply restart the "vz" service (definitely not preferable).
Even doing an ifdown and ifup for venet0 did not help.
Bringing up interface venet0:
Configuring interface venet0:
net.ipv4.conf.venet0.send_redirects = 0
RTNETLINK answers: Network is down
Some errors from log:
CPT ERR: d2dc60........
Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general?
This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices.
The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
Add the following to fstab where 192.168.1.125/Media is the samba share and where /home/homeuser/Downloads is where you want to mount.
Change user and pass to what is needed (if no pass is required it still works fine with the below).
//192.168.1.125/Media /home/homeuser/Downloads cifs user=guest,pass=bla 0 0
mount: wrong fs type, bad option, bad superblock on //192.168.1.125/Media,
I used the slightly older "304.117" version and it worked.
With the newest version I couldn't get X to start and kept getting these errors in messages/dmesg.
[ 2346.083660] nvidia 0000:01:00.0: irq 44 for MSI/MSI-X
[ 2350.608342] NVRM: RmInitAdapter failed! (0x12:0x2b:1831)
[ 2350.608354] NVRM: rm_init_adapter failed for device bearing minor number 0
[ 2350.608369] NVRM: nvidia_frontend_open: minor 0, module->open() failed, err........
Sep 26 16:56:21 box kernel: 00 00 00 00 00 00 00 00
Sep 26 16:56:21 box kernel: [37007.155690] d_alias libdl-2.12.so d_count=9 d_flags=8
Sep 26 16:56:21 box kernel: [37007.155697] 09 00 00 00 08 00 00 00 9f 05 9f 05 00 00 00 00 c0 71 1d 18 04 88 ff ff 00 00 00 00 00 00 00 00 a0 7e 48 00 00 c9 ff ff 78 a9 21 18 04 88 ff ff 3a 7b fa 4e 0d 00 00 00 98 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 18 5c 2d 18 04 88 ff ff 00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de f8........
When trying to reboot this Centos 5 container, it gets stuck as "mounted" and requires a manual start command, here is what dmesg shows:
[424458.173252] VE10000: no allowed mount options found for device 0:21
[424458.177970] proc: unrecognized mount option "relatime" or missing value
[424460.297663] CT: 10000: stopped
[426663.466433] CT: 10000: started........
I'm using ecryptfs and was suddenly unable to access or even ls my home directory (but every subfolder is accessible). It just hangs and throws this message in messages/dmesg:
Either the lower file is not in a valid eCryptfs format, or the key could not be retrieved. Plaintext passthrough mode is not enabled; returning -EIO
I read somewhere that perhaps some file or folder is owned by root somehow, sure enough there are some and sudoing to root allows me to........
I like badblocks and don't know a better more reliable way of checking the drive. If there are no errors from badblocks and dmesg doesn't produce any SATA related errors, the drive should be good (for now at least).
I also prefer to do read and write mode, yes it takes ages but it is really the best way of doing it. This gives me the most confidence in knowing that a drive, especially a new one is at least OK at the moment.
To test in read only mode........
I've encountered this problem before and I believe it may affect other drivers (I could test but I don't have time). This was happening on my custom Linux system with the pcnet32 driver.
pcnet32: eth0: transmit timed out, status 97fb, resetting (and some other kernel module tracing in dmesg)
Basically it means the card is connected (it shows connected in full duplex etc.. and recognized if the cable is disconnected too) but no packets can be sent or received........
I had a system running a 128MB live CD image with 2.8 gigs of available RAM and the OOM kernel killer went crazy when using dd for more than 8 minutes and kept killing everything. I've read that this is due to a low-memory issue and paging in the kernel and 32-bit systems with lots of RAM.
I even enabled swapspace on my LiveCD and the issue happened 25 minutes into dd rather than 8 minutes, so what gives?
Also no swap space was ever used!
I like dd, although it only reads it, usually a read test of the entire disk will uncover if your hard drive is bad in some parts. This is a good thing to do at least once a month, a lot of times bizarre program behavior, laginess and crashing/unnmounting problems etc.. are due to a failing disc and SMART won't know it or indicate a problem:
We must also remember there's never a guarantee, I've found that ever since we moved to larger and more platters per drive with 1TB drives........
high IO wait
424 root 39 19 1900 848 552 D 0.0 0.0 0:00.91 updatedb
root 424 0.0 0.0 1900 848 ? DN Mar11 0:00 /usr/bin/updatedb -f sysfs?rootfs?bdev?proc?cpuset?binfmt_misc?debugfs?sockfs?usbfs?pipefs?anon_inodefs?futexfs?tmpfs?inotifyfs?eventp........
This doesn't seem to be widely known (maybe it's in some documentation that none of us read though) but there's an easy way to check the integrity of any mdadm array:
sudo echo check > /sys/block/md0/md/sync_action
-bash: /sys/block/md0/md/sync_action: Permission denied
sudo will never work, this only works as root since echo is not actually a binary/command. It is built-into bash.
I separated the 2 drives in the RAID 1 array.
1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated).
I wonder how mdadm will handle this:
usb-storage: device scan complete
md: md127 stopped.
md: md127: raid array is not clean -- starting background reconstruction
raid1: raid set md127 active with 1 out of 2 m........
It's not just as simple as running the chroot command, you need to ensure the /proc and /dev entries are passed through and populated to the chroot environment.
Step 1 - Mount Your Off-line OS
mount /dev/sda1 /mnt
Step 2 - Mount Proc
mount -t proc none /mnt/proc
Step 3 - Mount Dev
Most guides will tell you to use this: mount -o bind /dev /mnt//dev but that doesn't work for some reason in many cases:
Out of memory: kill process 7559 (rsync) score 635 or a child
Killed process 7559 (rsync)
I was surprised to see this in my dmesg when my rsync backup suddenly stalled/stopped.
This system has 3 gigs of RAM and lots of free memory so I don't understand what is happening.
rsync invoked oom-killer: gfp_mask=0x200d2, order=0, oomkilladj=0
Pid: 7600, comm: rsync Not tainted 188.8.131.52 #83
The dmg format is silly and annoying to work with, why couldn't Apple stick with the .iso standard? Anyway, there's an excellent Linux and Windows based tool to convert it back to a normal .iso Image called dmg2iso
I'll only cover the Linux version although the Windows pre-built binary works the same way.
Download dmg2iso here for free (from the author's website)
It's just silly and doesn't make sense that Ubuntu doe........
This will give you the basic info needed to browse and connect to Samba shares from the command line. From the GUI of Gnome or KDE etc, it is pretty standard and straight forward. However, I've found very little guides on how to do it from the command line and if you're like me, a nerd who prefers command line for its simplicity and for remote use, this is the way to go.
First get a list of all the Samba/SMB shares on the target.
smbclient -L hostname........