Linux : Cannot Access …. Input/output error

/bin/ls: reading directory .: Input/output error
total 0

The above error indicate that i cannot access to the specific file on Linux, Delete not working. with root user as well.
so the error is not a problem to delete files, it’s a problem about the file system itself and/or an hardware problem, but before announce that it’s hardware issue 🙂 try the below solution :-

 Option #1:-

use command dmesg.

(display message or driver message) is a command on most Linux- and Unix-based operating systems that prints the message buffer of the kernel. Read about that command here

Option #2 ( worked for me)

Use Fsck command to detect filesystem error and fix it.

How !!!

  1.  First Umount File system ( that file located ). Using Umount command if it’s not able to un mount the file system use lsof command or fuser to check which user using this filesystem.
  2. run the fsck -y /dev/…………….. 
  3. mount file system again.
Fsck Command here
Cheers
Osama …

Extend LVM Disk Linux

This Article Will Describe step by step how to extend LVM Disk On Linux :-

1- After adding New Harddisk to the server you have to ReScan The Scsi using 

echo “- – -” > /sys/class/scsi_host/host?/scan

? :- Depend on you host number. 

2-  Use Fdisk to create new partition.

>fdisk -l
Disk /dev/sda: 107.3 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          13      104391   83  Linux
/dev/sda2              14       13054   104751832+  8e  Linux LVM
Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn’t contain a valid partition table

 Check the below :-

#fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklab el
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won’t be recoverable.

The number of cylinders for this disk is set to 1305.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-1305, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-1305, default 1305):
Using default value 1305

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.

3-  Lets start increasing :-

pvcreate /dev/sdb1
Writing physical volume data to disk “/dev/sdb1”
Physical volume “/dev/sdb1” successfully created

vgdisplay
— Volume group —
VG Name Oracle
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 99.88 GB
PE Size 32.00 MB
Total PE 3196
Alloc PE / Size 3196 / 99.88 GB
Free PE / Size 0 / 0
VG UUID MZ04D3-jZLy-0BWi-2WSP-oi9E-hBkl-e3a08d

vgextend Oracle /dev/sdb1  Volume group “Oracle” successfully extended

 pvscan
  PV /dev/sda2   VG Oracle   lvm2 [99.88 GB / 0    free]
  PV /dev/sdb1   VG Oracle   lvm2 [9.97 GB / 9.97 GB free]
  Total: 2 [109.84 GB] / in use: 2 [109.84 GB] / in no VG: 0 [0   ]

###

lvdisplay
— Logical volume —
LV Name /dev/Oracle/LogVol00
VG Name Oracle
LV UUID wKMZ16-LHsc-ktsc-3dTT-ieiq-pEfT-tODhqc
LV Write Access read/write
LV Status available
# open 1
LV Size 9.75 GB
Current LE 312
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:0

— Logical volume —
LV Name /dev/Oracle/LogVol02
VG Name Oracle
LV UUID UabZCO-G8ID-dh1a-xv6t-Ss4O-QqEx-fnIy5g
LV Write Access read/write
LV Status available
# open 1
LV Size 82.34 GB
Current LE 2635
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:1

— Logical volume —
LV Name /dev/Oracle/LogVol01
VG Name Oracle
LV UUID 78Y3bv-UZZI-Iu2w-gAyD-HXe1-Fx25-gmGuKn
LV Write Access read/write
LV Status available
# open 1
LV Size 7.78 GB
Current LE 249
Segments 1
Allocation inherit
Read ahead sectors auto
– currently set to 256
Block device 253:2

Now Let’s Extend :-

lvextend /dev/Oracle/LogVol00 /dev/sdb1 Extending logical volume LogVol00 to 19.72 GB
Logical volume LogVol00 successfully resized

 Finally :-

resize2fs /dev/Oracle/LogVol00resize2fs 1.39 (29-May-2006)
Filesystem at /dev/Oracle/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/Oracle/LogVol00 to 5169152 (4k) blocks.

Notes :

  1. The Red Color for Command Line.
  2. The Brown Color For necessary Output. 
  3. /dev/Oracle/LogVol00 it’s the name for LVM Disk.
  4. /dev/sdb1 disk that we created using fdisk.

Thank you
Osama Mustafa

Enable Samba to Share from Linux to Windows

To Setup and configure Shared Folder From Linux to Windows Follow the Below Steps :-

  • Install Samba Package on OS using the below command.
    • rpm -ivh samba Or yum install samba
  • After Install The Package configure   Username and password using the below command :-
    • smbpasswd -a oracle ( Or Any other user you want to share folder with )
  • On Linux Side –> Create Directory using mkdir /u01/share.
  • edit vi /etc/samba/smb.conf and configure the file to allow share to the above folder.

[Folder-name]
path = Folder_path
available = yes
valid users = User_will_user_folder.
read only = no
browsable = yes
public = yes
writable = yes

  • Restart Samba Services –> service smb restart
  • On Windows you can access the folder using Run –> \\Linux-Ip and enter the username and password.

Thank you
Osama Mustafa

Oracle Solaris 11.2 Launch On 29/04

Today 29/04/2014 Oracle Launched new version of operating system Solaris 11.2, This Version will contain significant Features and it’s fully supported for Cloud

Some of the new features :-

  • Reduce management effort via OpenStack integration
  • Further increase the flexibility of Solaris system virtualization
  • Add unique software-defined networking (SDN) capabilities
  • Simplify the creation of private and public clouds

The Link for the Event Here.

Thank you 
Osama mustafa

Oracle Linux 7 Beta Released

Oracle has announced that the initial beta build of Oracle Linux 7.0,a distribution built from source for
Red Hat and enhanced with an “unbreakable” Linux kernel and now it’s Ready for your Testing.

  • RHEL 7 Will now format drives with the XFS filesystem by default.
  • enabling volumes of up to 500TB in size.
  •  if you prefer the older ext4 filesystem it’s now supports 50TB volumes. 
  • improves support for large-scale enterprise storage arrays.
  • provides new tools for managing heterogeneous storage.
  • New Version of SAMBA 4.1.
You Can Download it From Here.
Thank you
Osama mustafa

Flush Linux Buffer Cache

Cache is used to keep data to use frequently by operating system,  But sometimes memory is getting low linux provide some memory Command line to monitor Memory status Check the below link :-

1- Linux Check Memory Usage Here.
2- 18 Command Line Tools to Monitor Linux Performance here.

There are options available to flush cache of linux memeory :-

Flush everything ( Pagecache, dentries and inodes )  :-

 sync; echo 3 > /proc/sys/vm/drop_caches.

Flash dentries and inodes :-

 sync; echo 2 > /proc/sys/vm/drop_caches

Flash PageCache only

sync; echo 1 > /proc/sys/vm/drop_caches

All the command should be Run As root.

Schudle the above command as job using crontab , choose from the above command what you need :-

0  *  *  *  *  /root/memory.sh

Memorysh –> should be contain one the above script run as root.

Thank you
Osama mustafa

 

Enable SSH On Windows EM12C Purpose

Uploading Agent to windows/Linux needs ssh Port to be open and enabled, ssh not enabled on windows by default and do it Cygwin should be installed.

Configure Cygwin so simple, follow the below steps :-

Download Cygwin from Here, Upload File to the windows Server and Run the setup.

SSH Package should be chosen while installation.
After Installation Run cygwin terminal as Administration ( Right click on the icon and Choose the option )
Now Enable ssh should be done by run below command :-

/usr/bin/ssh-host-config

Should privilege separation be used? (yes/no) yes
new local account ‘sshd’? (yes/no) yes
Do you want to install sshd as a server? Yes
Enter the value of CYGWIN for the daemon: [] (DON’T ENTER ANYTHING, PRESS ENTER)
Do you want to use a different name? (yes/no) no
Create new privileged user account ‘cyg_server’? (yes/no) yes
Please enter the password: ENTER YOUR PASSWORD HERE
Reenter: RE-ENTER YOUR PASSWORD

Using Command Prompt ( cmd )

Start ssh by –> net start sshd
Stop ssh by –> net stop sshd

Another way posted by my friend Maaz you can check it here.

Thank you 
Osama Mustafa

soft limit maximum user processes/Oracle Linux

As Root User access to
[root@EM12C Packages]# vi /etc/security/limits.conf

Then add the below line or modify it :

oracle              soft    nproc   2047
oracle              hard    nproc   16384
oracle              soft    nofile  4096
oracle              hard    nofile  65536
oracle              soft    stack   10240

Thank you
Osama Mustafa 

Share Folder as File System From Windows to Linux

in this post i will show you how to share folder from windows to Linux , you can use smb but in this post i will use it in command line.

Option #1:
SMB

By Press ( ALT+F2 ) the new dialog will be opened just type in the box the below :

smb://windows-server-ip/shared folder 

Option #2: 
Using command line.
  • mkdir /windows-backup
  • as root user
  • mount -t cifs //windowsip/sharefolder -o username=administrator,password=administratorpassword /windows-backup.
  • run df -h to make sure the folder has been mounted.
Note :
If you are using RHEL 4 the above command will not work, check the below

mount -t smbfs -o username=administrator,password=administratorpassword //windowsip/backup /windwos-backup

Thank you
Osama mustafa

Reference :
1- cyberciti Here