yael's questions

As we all know, we can type banner in /etc/motd or in the file /etc/issue.net, so every user that login to the Linux machine will get the banner message, for example:

Red Hat Enterprise Linux Server release 6.8 (Santiago)
Kernel \r on an \m
##########################################################################
#                               Welcome to OBAMA house !!!
#                         All connections are monitored and recorded
#                Disconnect IMMEDIATELY if you are not an authorized user!
#
##########################################################################

The problem is that the banner is displayed also when we login remotely via ssh to the Linux machines (as opposed to login locally).

We can simply ignore the banner in the ssh by using the flag -q as the following:

ssh -q  192.19.23.45 ls /hillary_emails 

In fact we have more then ~100 Bash and Perl scripts that use ssh, so if we add banners to all the machines we need to change also the scripts that use the ssh command, by adding the flag -q (silent mode).

We prefer not to edit the scripts, due to internal reasons. So my question is, is it possible to change the Linux client configuration in a way the banner will display only on local logins, and not display when login remotely by ssh?

we have red-hat version 6.x machine,

I verified what are the missing security patches as the following:

 yum updateinfo list security available
 Loaded plugins: product-id, rhnplugin, security, subscription-manager
 This system is receiving updates from RHN Classic or RHN Satellite.
 RHSA-2016:0073 security bind-libs-32:9.8.2-0.37.rc1.el6_7.6.x86_64
 RHSA-2016:0073 security bind-utils-32:9.8.2-0.37.rc1.el6_7.6.x86_64
 RHSA-2016:0428 security libssh2-1.4.2-2.el6_7.1.x86_64
 RHSA-2016:0007 security nss-3.19.1-8.el6_7.x86_64
 RHSA-2016:0007 security nss-sysinit-3.19.1-8.el6_7.x86_64
 RHSA-2016:0007 security nss-tools-3.19.1-8.el6_7.x86_64
 RHSA-2016:0370 security nss-util-3.19.1-5.el6_7.x86_64
 RHSA-2016:0063 security ntp-4.2.6p5-5.el6_7.4.x86_64
 RHSA-2016:0063 security ntpdate-4.2.6p5-5.el6_7.4.x86_64
 RHSA-2016:0008 security openssl-1.0.1e-42.el6_7.2.x86_64
 RHSA-2016:0301 security openssl-1.0.1e-42.el6_7.4.x86_64
 RHSA-2016:0005 security rpcbind-0.2.0-11.el6_7.x86_64
 updateinfo list done

I have two questions:

when I run the following yum command:

yum update -y

dose this yum command will be installed all the missing security patch?? ( as I mentioned in the list )

when yum update -y completed to installed all patches ,

is it mean that my Linux red-hat machine version 6.x is fully updated with all patches?

I use the atop in order to verify the performance top history and know by the values the status for each time

my question is ,

what the alternative for atop that can view the values in chart?

or maybe some tool that can get the atop logs and convert these values to a chart

My target is to increase the ring buffer ( I have Linux red-hat 7.1 ) , but I get the following:

ethtool -G eth1 rx 8192
Cannot set device ring parameters: Invalid argument

so how to enable this value? , or maybe this is the MAX value?

the current status:

ethtool -g eth1
Ring parameters for eth1:
Pre-set maximums:
RX:             4096
RX Mini:        0
RX Jumbo:       0
TX:             4096
Current hardware settings:
RX:             256
RX Mini:        0
RX Jumbo:       0
TX:             512

Remark - I want to increase the ring buffer because errors - pkts rx OOB - indicate that the network card is out of buffer

# ethtool -i eth1
  driver: vmxnet3
  version: 1.1.30.0-k-NAPI
  firmware-version:
  bus-info: 0000:1b:00.0
  supports-statistics: yes
  supports-test: no
  supports-eeprom-access: no
  supports-register-dump: yes
  supports-priv-flags: no


  more /etc/modprobe.d/blacklist.conf
  blacklist ipv6


  more /etc/sysconfig/network-scripts/ifcfg-eth1

  MTU=9000
  DEVICE=eth1
  HWADDR=70:10:76:9E:02:81
  TYPE=Ethernet
  ONBOOT=yes
  BOOTPROTO=static
  NETMASK=255.255.255.0
  IPADDR=12.160.0.36


  modinfo vmxnet3
  filename:       /lib/modules/3.10.0-    229.14.1.el7.x86_64/kernel/drivers/net/vmxnet3/vmxnet3.ko
  version:        1.1.30.0-k
  license:        GPL v2
  description:    VMware vmxnet3 virtual NIC driver
  author:         VMware, Inc.
  rhelversion:    7.1
  srcversion:     EF80BF71B6F577C3370F410
  alias:          pci:v000015ADd000007B0sv*sd*bc*sc*i*
  depends:
  intree:         Y
  vermagic:       3.10.0-229.14.1.el7.x86_64 SMP mod_unload modversions
  signer:         Red Hat Enterprise Linux kernel signing key
  sig_key:         44:02:00:8F:2B:3F:DA:1F:6C:1C:64:BA:2C:10:BF:0C:FE:EC:AB:B7
  sig_hashalgo:   sha256

please advice what could be the root cause for dropped problem as the following: ( dropped 2201101 ) on Linux red-hat 7.1

    eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 9000
    inet 12.196.92.19  netmask 255.255.255.0  broadcast 12.196.92.255
    ether 01:j0:56:9f:01:2d  txqueuelen 1000  (Ethernet)
    RX packets 232527230  bytes 1889668645608 (1.7 TiB)
    RX errors 0  dropped 2201101  overruns 0  frame 0
    TX packets 197267008  bytes 455540267580 (424.2 GiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0



  ethtool -S eth1
  NIC statistics:
  Tx Queue#: 0
     TSO pkts tx: 0
     TSO bytes tx: 0
     ucast pkts tx: 27261
     ucast bytes tx: 5684138
     mcast pkts tx: 0
     mcast bytes tx: 0
     bcast pkts tx: 6
     bcast bytes tx: 252
     pkts tx err: 0
     pkts tx discard: 0
     drv dropped tx total: 0
       too many frags: 0
       giant hdr: 0
       hdr err: 0
       tso: 0
     ring full: 0
     pkts linearized: 0
     hdr cloned: 0
     giant hdr: 0
    Tx Queue#: 1
      TSO pkts tx: 0
      TSO bytes tx: 0
      ucast pkts tx: 138
      ucast bytes tx: 12312
      mcast pkts tx: 0
      mcast bytes tx: 0
      bcast pkts tx: 0
      bcast bytes tx: 0
      pkts tx err: 0
      pkts tx discard: 0
      drv dropped tx total: 0
         too many frags: 0
         giant hdr: 0
         hdr err: 0
         tso: 0
      ring full: 0
      pkts linearized: 0
      hdr cloned: 0
      giant hdr: 0
    Rx Queue#: 0
      LRO pkts rx: 0
      LRO byte rx: 0
      ucast pkts rx: 123
      ucast bytes rx: 10936
      mcast pkts rx: 0
      mcast bytes rx: 0
      bcast pkts rx: 13496
      bcast bytes rx: 859036
      pkts rx OOB: 0
      pkts rx err: 0
     drv dropped rx total: 0
        err: 0
       fcs: 0
       rx buf alloc fail: 0
      Rx Queue#: 1
      LRO pkts rx: 2613
      LRO byte rx: 40902978
      ucast pkts rx: 27979
      ucast bytes rx: 128670918
      mcast pkts rx: 0
      mcast bytes rx: 0
      bcast pkts rx: 255
      bcast bytes rx: 34445
      pkts rx OOB: 0
      pkts rx err: 0
      drv dropped rx total: 0
      err: 0
      fcs: 0
      rx buf alloc fail: 0
      tx timeout count: 0

I used the RHN - red-hat satellite version 5.x in order to install errata patch: ( on linux version 6.x ) glibc-2.12-1.166.el6_7.7.x86_64

while the curent patch on my linux was:

glibc-devel-2.12-1.166.el6_7.3.x86_64

WITH RHN the patch installed successfully.

But now I want to return to the previous patch version -

 glibc-devel-2.12-1.166.el6_7.3.x86_64

Please advise how can I perform downgrade process with RHN?

What are the steps required in order to perform the downgrade?

from my linux machine:

# yum history info | tail -5
    Updated glibc-devel-2.12-1.166.el6_7.3.x86_64   @rhel-x86_64-server-6
    Update              2.12-1.166.el6_7.7.x86_64   @rhel-x86_64-server-6
    Updated glibc-headers-2.12-1.166.el6_7.3.x86_64 @rhel-x86_64-server-6
    Update                2.12-1.166.el6_7.7.x86_64 @rhel-x86_64-server-6
    history info

is it possible to know when partition was mounted from storage volume?

for example latly we know about that netapp19:/volume/orsdcp_nfs was mounted on /oraT

but how to know when? ( regarding that we not have info from history command )

 14:28:01 root@serverFF100:/ # df -h
  Filesystem                           Size  Used Avail Use% Mounted on
 /dev/mapper/rootvg-slash             60M  431M  168M  73% /
 tmpfs                                5.G  8.0K  5.9G   1% /dev/shm
 /dev/mapper/opt                      92M  445M  496M  48% /opt
 /dev/mapper/hds                      5G  2.0G  2.8G  42% /opt/hds
 /dev/mapper/usr                      1.G  996M  320M  76% /usr
 /dev/mapper/var                      3G  853M  2.0G  30% /var
 /dev/mapper/home                     28M   40M  196M  17% /home
 /dev/sdb1                            16M   69M   78M  47% /boot
 tmpfs                                3.2G   52K  3.0G   1% /tmp
 netapp10:/volume/eedfede/ildgdb01       1G   50G   65G  44% /erfa
 netapp10:/volume/lwdefe_nfs             77G  713G   54G  94%       /ora/data/lgrerrd
 netapp10:/volume/sdfdcv_nfs             49G   41G  360G  11%   /ora/data/sddfed
 netapp19:/volume/orsdcp_nfs             89G   82G  778G  10% /oraT

As in the picture below, my Linux machine was hung and I couldn't login.

How do I identify the reason for the "hang", according to the messages on the console?

I searched /var/log/messages for more info (but I get lost in there, can't find anything useful), but I do not know exactly where to find core files.

What are the other files that we can find info in for this situation ?

I have linux VM machines with version red-hat 4

I have the following file system

df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2             950M  163M  739M  19% /
/dev/sda1             130M   13M  118M  10% /boot
none                  2.0G     0  2.0G   0% /dev/shm
/dev/sda6              96M   18M  899M   2% /tmp
/dev/sda3             2.8G  1.2G  1.5G  44% /usr
/dev/sda5               5G  152M  765M  17% /var

I need to install some oracle KIT that need /tmp at least 2G , while my free /tmp is 96M

Can someone advice what my alternative? In order to install my oracle KIT

Not sure but I was thinking about to create link from /tmp to /usr but I guess I will stay with the same problem , or maybe some other creative solution ?

Please advice

I want to create with sed the following:

for example each word in the file that have the "ssss..." Should be replaced (all word) with target string as gggg

 echo "duwdbnhb ssssssmnfkejfnei" | sed s'/ssssss*/gggg/g'

 duwdbnhb ggggmnfkejfnei

should be:

 duwdbnhb gggg

remark - string could be with couple of "s" strings ( for example ss or sss or ssssss )

example:

 echo "duwdbnhb sssmnfkejfnei" | sed s'/s*/gggg/g'

 duwdbnhb gggg



 echo "duwdbnhb sssmnfdej3434bjhhji" | sed s'/s*/gggg/g'

 duwdbnhb gggg

I am using VMware version 5.5 (that manage 57 different VM Linux machines –red-hat version 6 until 7 ) In the VSphere Client (tasks and event), I saw the following error: (on Linux machine name – Korfo_prod43 )

An error occurred while saving the snapshot msg.snap-hot error –Q- UIESCINGERROR

And when I try to log via SSH to the Linux machine, I notice that Linux machine is Hung (freeze state), so only reboot was needed to start up again the machine

In order to find a resolution for the snapshot problem,

I find the following resolution but not sure if this resolution is completely fit for my problem?

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2116120