Changing Broadcom Driver In Ubuntu

I have a Broadcom Wireless Network Adapter and I had all sort of problem with the standard driver, Broadcom STA Wireless driver or wl that the module is called.

To identify which Broadcom chipset you have. Run:

$ lspci -vvnn | grep 14e4
45:00.0 Network controller [0280]: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter [14e4:4727] (rev 01)

To identify which modules (driver) you are using (running):

$ egrep 'ssb|wl|brcmfmac|brcmsmac|bcma' /proc/modules 

I had the STA or wl module running. To remove all possible Broadcom modules.

$ sudo modprobe -r b43 ssb wl brcmfmac brcmsmac bcma 

And to really remove the default STA or wl module, also remove the debian package. After the purge, that remove configuration files as well, I double run apt-get with remove autoremove, which will remove unused package and finally I run clean, to clean the apt-get cache. All for precaution.

$ sudo apt-get purge bcmwl-kernel-source && sudo apt-get autoremove && sudo apt-get clean

Now you must test which driver/module that suites you best. I started with the b43 driver/module.

$ sudo apt-get install firmware-b43-installer
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  b43-fwcutter
The following NEW packages will be installed:
  b43-fwcutter firmware-b43-installer
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 22.8 kB of archives.
After this operation, 120 kB of additional disk space will be used.
Do you want to continue [Y/n]? Y

To load the new module/driver.

$ sudo modprobe b43

Now test you installation, if successful reboot and double check, that everything is working correctly..

Other possible driver are b43legacy package firmware-b43legacy-installer and LP-PHY package firmware-b43-lpphy-installer.

For more hardware commands, please read http://magnus-k-karlsson.blogspot.se/2013/01/how-to-install-atheros-ar8161-ethernet.html

Reference

• help.ubuntu.com : WifiDocs/Driver/bcm43xx

The Medibuntu Project has come to an end

For many people the first thing they have done after installing Ubuntu, was to add the Medibuntu repository. But now it is dead. See announcement Here.

But what is the impact? Not much. Ubuntu already offers most of the things that existed in Medibuntu and this only natural progress of the growth of Ubuntu.

Managing Network in RHEL 6

Tools

The simplest way to manage network settings is to use the system-config-network tool or the non-graphical variant system-config-network-tui

To start, stop, status all our network devices

$ service network [start|stop|status|restart]

Other useful tools are:

ifconfig	Display our network settings.
ping	Used for check network connectivity
route -n	Display routing and Gateway
traceroute	Display network routing to a host.
netstat -nr	Display open ports.

Configuration

Main network configuration file is /etc/sysconfig/network-scripts/ifcfg-<name>.

Hostname

$ hostname 
tester1.example.com

Routing

Local routing for e.g. localhost, but also for static routing.

$ cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Main routing configuration file. Any changes will be overwritten, unless disabled in above sysconfig network-scripts with PEERDNS=no.

$ cat /etc/resolv.conf 
$ Generated by NetworkManager
search example.com
nameserver 192.168.1.1

Reference

• network-scripts: /usr/share/doc/initscripts-<version>/sysconfig.txt

Using the Automounter Service on RHEL 6

RHEL 6 ships with a convenient network mounter service, the automounter.

To check if the automounter is running.

$ service autofs status
automount (pid  2061) is running...

To use it, simply cd into the /net folder followed by nfs hostname.

$ cd /net/192.168.1.3
[root@tester1 192.168.1.3]# ll
total 0
dr-xr-xr-x. 4 root root 0 Nov 27 22:25 c

The remote network share will be unmounted automatically when unused for a configurable timeout.

$ grep -i timeout /etc/sysconfig/autofs 
...
TIMEOUT=300
...

Managing LVM with RHEL 6

Introduction

LVM (Logical Volume Manager) is a flexible way to handle disk space, since you can increase and decrease file systems, that is not possible to the same extent as in MBR (Master Boot Record) partitioning format.

NOTE: "It is generally recommended that you create a single partition that covers the whole disk to label as an LVM physical volume" [https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/LVM_components.html#multiple_partitions]

The LVM is build up on three cornerstone.

1. Physical Volume, PV
2. Volume Group, VG
3. Logical Volume, LV

Prerequisite

Create a new partition with type 0x8E Linux LVM.

$ fdisk -cu /dev/sda

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 3
First sector (205826048-488397167, default 205826048): 
Using default value 205826048
Last sector, +sectors or +size{K,M,G} (205826048-488397167, default 488397167): +1G

Command (m for help): t
Partition number (1-4): 3
Hex code (type L to list codes): L

 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        
 1  FAT12           39  Plan 9          82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      3c  PartitionMagic  83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      41  PPC PReP Boot   85  Linux extended  c7  Syrinx         
 5  Extended        42  SFS             86  NTFS volume set da  Non-FS data    
 6  FAT16           4d  QNX4.x          87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS       4e  QNX4.x 2nd part 88  Linux plaintext de  Dell Utility   
 8  AIX             4f  QNX4.x 3rd part 8e  Linux LVM       df  BootIt         
 9  AIX bootable    50  OnTrack DM      93  Amoeba          e1  DOS access     
 a  OS/2 Boot Manag 51  OnTrack DM6 Aux 94  Amoeba BBT      e3  DOS R/O        
 b  W95 FAT32       52  CP/M            9f  BSD/OS          e4  SpeedStor      
 c  W95 FAT32 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi eb  BeOS fs        
 e  W95 FAT16 (LBA) 54  OnTrackDM6      a5  FreeBSD         ee  GPT            
 f  W95 Ext'd (LBA) 55  EZ-Drive        a6  OpenBSD         ef  EFI (FAT-12/16/
10  OPUS            56  Golden Bow      a7  NeXTSTEP        f0  Linux/PA-RISC b
11  Hidden FAT12    5c  Priam Edisk     a8  Darwin UFS      f1  SpeedStor      
12  Compaq diagnost 61  SpeedStor       a9  NetBSD          f4  SpeedStor      
14  Hidden FAT16 <3 63  GNU HURD or Sys ab  Darwin boot     f2  DOS secondary  
16  Hidden FAT16    64  Novell Netware  af  HFS / HFS+      fb  VMware VMFS    
17  Hidden HPFS/NTF 65  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE 
18  AST SmartSleep  70  DiskSecure Mult b8  BSDI swap       fd  Linux raid auto
1b  Hidden W95 FAT3 75  PC/IX           bb  Boot Wizard hid fe  LANstep        
1c  Hidden W95 FAT3 80  Old Minix       be  Solaris boot    ff  BBT            
1e  Hidden W95 FAT1
Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)

Command (m for help): p

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x7f3d8c0f

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048   205826047   102400000   8e  Linux LVM
/dev/sda3       205826048   207923199     1048576   8e  Linux LVM

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 or after you run partprobe(8) or kpartx(8)
Syncing disks.

$ reboot

The Most Imported Commands

$ man 8 lvm
...
pvcreate - Initialize a disk or partition for use by LVM.
pvdisplay - Display attributes of a Physical Volume.
...
vgcreate - Create a Volume Group.
vgdisplay - Display attributes of Volume Groups.
vgextend - Add Physical Volumes to a Volume Group.
vgreduce - Reduce a Volume Group by removing one or more Physical Volumes.
...
lvcreate - Create a Logical Volume in an existing Volume Group.
lvdisplay - Display attributes of a Logical Volume.
lvextend - Extend the size of a Logical Volume.
lvreduce - Reduce the size of a Logical Volume.

Create Physical Volume (PV), Volumme Group (VG) and Logical Volume (LV)

First lets create a new physical volume on the prerequisite partition.

$ pvcreate /dev/sda3 

Create volume group vg_test that span entire physical volume /dev/sda3

$ vgcreate vg_test /dev/sda3 
  Volume group "vg_test" successfully created

Create logical volumne with size 500 MB, named lv_test in volume group vg_test.

$ lvcreate -L 500M -n lv_test vg_test

The lvcreate will now create a device block file in /dev/vgName/lvName that we now can create a filesystem on and mount.

$ mkfs -t ext4 /dev/vg_test/lv_test
$ mkdir /data
$ mount /dev/vg_test/lv_test /data

Extends Logical Volume (LV)

Extend the logical volume lv_test with plus 500 MB.

$ lvextend -L +250M /dev/vg_test/lv_test 
  Rounding size to boundary between physical extents: 252.00 MiB
  Extending logical volume lv_test to 752.00 MiB
  Logical volume lv_test successfully resized

Now you need to grow the file system.

$ resize2fs -p /dev/vg_test/lv_test
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg_test/lv_test is mounted on /data; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 3
Performing an on-line resize of /dev/vg_test/lv_test to 770048 (1k) blocks.
The filesystem on /dev/vg_test/lv_test is now 770048 blocks long.

Verify/test the new size of /data.

$ df -h /data

Reduce Logical Volume (LV)

When reducing a file system, you need to unmount it first.

$ umount /data

Then reduce the actual filesystem.

$ e2fsck -f /dev/vg_test/lv_test

$ resize2fs -p /dev/vg_test/lv_test 512M
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/vg_test/lv_test to 524288 (1k) blocks.
Begin pass 3 (max = 94)
Scanning inode table          XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
The filesystem on /dev/vg_test/lv_test is now 524288 blocks long.

After the actual file system is reduced, we can now shrink the logical volume.

$ lvreduce -L 512M /dev/vg_test/lv_test 
  WARNING: Reducing active logical volume to 512.00 MiB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv_test? [y/n]: y
  Reducing logical volume lv_test to 512.00 MiB
  Logical volume lv_test successfully resized

Finally test/verify, by remounting and check disk space

$ mount /dev/vg_test/lv_test /data
$ df -h /data
Filesystem                   Size  Used Avail Use% Mounted on
/dev/mapper/vg_test-lv_test  496M   11M  461M   3% /data

Extends Volume Group (VG)

First create a new physical volume.

$ pvcreate /dev/sda4
  Physical volume "/dev/sda4" successfully created

Now lets extends existing volume group 'vg_test' with our new physical volume.

$ vgextend vg_test /dev/sda4 
  Volume group "vg_test" successfully extended

And last test/verify.

$ vgdisplay vg_test
  --- Volume group ---
  VG Name               vg_test
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               134.73 GiB
  PE Size               4.00 MiB
  Total PE              34492
  Alloc PE / Size       128 / 512.00 MiB
  Free  PE / Size       34364 / 134.23 GiB
  VG UUID               ItBewY-gWvu-tzUx-JIEj-gJb2-d8Jh-HdANUb

Reduce Volume Group (VG)

Remove existing volume group 'vg_test' with physical volume /dev/sda4.

$ vgreduce vg_test /dev/sda4
  Removed "/dev/sda4" from volume group "vg_test"

Test/verify

$ vgdisplay vg_test
  --- Volume group ---
  VG Name               vg_test
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1020.00 MiB
  PE Size               4.00 MiB
  Total PE              255
  Alloc PE / Size       128 / 512.00 MiB
  Free  PE / Size       127 / 508.00 MiB
  VG UUID               ItBewY-gWvu-tzUx-JIEj-gJb2-d8Jh-HdANUb

Reference

• lvm(8): lvm - LVM2 tools
• pvcreate(8): pvcreate - initialize a disk or partition for use by LVM
• vgcreate(8): vgcreate - create a volume group
• lvcreate(8): lvcreate - create a logical volume in an existing volume group
• vgextend(8): vgextend - add physical volumes to a volume group
• vgreduce(8): vgreduce - reduce a volume group
• lvextend(8): lvextend - extend the size of a logical volume
• lvreduce(8): lvreduce - reduce the size of a logical volume
• resize2fs(8): resize2fs - ext2/ext3/ext4 file system resizer

Encrypting Disks with LUKS in RHEL 6

Introduction

LUKS (Linux Unified Key Setup) is a standard for hard disk encryption. LUKS can encrypt both partition and LVM volumes. Here I will encrypt a partition.

Prerequisite

Creata a new partition with fdisk.

$ fdisk -cu /dev/sda

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 3
First sector (205826048-488397167, default 205826048): 
Using default value 205826048
Last sector, +sectors or +size{K,M,G} (205826048-488397167, default 488397167): +1G

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 or after you run partprobe(8) or kpartx(8)
Syncing disks.

$ reboot 

Enrypt a Partition

First we need to encrypt the partition.

$ cryptsetup luksFormat /dev/sda3 

WARNING!
========
This will overwrite data on /dev/sda3 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter LUKS passphrase: 
Verify passphrase: 

Next step is to unlock the partition via luksOpen <blockDeviceFile> <luksname>. The cryptsetup will after create a new mapped blocked device file under /dev/mapper/<luksname>.

$ cryptsetup luksOpen /dev/sda3 luksname
Enter passphrase for /dev/sda3:  

Finally we format now the unencrypted partition we a file system and mount it.

$ mkfs -t ext4 /dev/mapper/luksname
$ mkdir /mnt/secret
$ mount /dev/mapper/luksname /mnt/secret

Persistently Mount Encrypted Partition

To make the mounting persisted we normally add the block device file in /etc/fstab, but with encrypted storage we also need to add the encrypted partition to the list of devices to be unlocked during system startup. That is done by adding the luksname and block device file to the /etc/crypttab.

$ vi /etc/crypttab

luksname    /dev/sda3

After that extra step, normally edit /etc/fstab.

$ vi /etc/fstab

/dev/mapper/luksname      /mnt/secret             ext4    defaults        1 2

Automatically Mount Encrypted Partition

To automatically unlock a encrypted partition we need to store the password on disk, has obvious security problems, but if wanted to the following.

$ echo -n "redhat" > /root/lukspassword
$ chown root:root /root/lukspassword
$ chmod 600 /root/lukspassword
$ ll /root/
...
-rw-------. 1 root root     6 Nov 27 12:12 lukspassword

$ cryptsetup luksAddKey /dev/sda3 /root/lukspassword

Now edit /etc/crypttab and add password file.

$ vi /etc/crypttab

luksName    /dev/sda3   /root/lukspassword

Reboot and verify, that no password is needed and that encrypted partition is mounted.

Remove Encrypted Partition

1. Remove mapped block device file from /etc/fstab.
2. Remove luksName from /etc/crypttab.
3. unmount the mapped block device: umount /dev/mapper/luksname.
4. Lock encrypted partition: cryptsetup luksClose luksname.

Reference

• cryptsetup(8): cryptsetup - setup cryptographic volumes for dm-crypt (including LUKS extension)
• crypttab(5): /etc/crypttab - encrypted block device table
• fstab(5): /etc/fstab - static information about the filesystems

Managing Swap Space in RHEL 6

Introduction

The swap space is used by the OS to handle overflow for parts of the RAM that are currently not being used.

The recommended size of the swap space is depending on how much RAM you have.

• < 2GB RAM, use 2 * RAM
• >= 2GB RAM, use RAM + 2GB

How to Create a New Swap Partition

$ fdisk -cul /dev/sda

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x7f3d8c0f

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048   205826047   102400000   8e  Linux LVM
$ fdisk -cu /dev/sda

Command (m for help): m
Command action
   a   toggle a bootable flag
   b   edit bsd disklabel
   c   toggle the dos compatibility flag
   d   delete a partition
   l   list known partition types
   m   print this menu
   n   add a new partition
   o   create a new empty DOS partition table
   p   print the partition table
   q   quit without saving changes
   s   create a new empty Sun disklabel
   t   change a partition's system id
   u   change display/entry units
   v   verify the partition table
   w   write table to disk and exit
   x   extra functionality (experts only)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 3
First sector (205826048-488397167, default 205826048): 
Using default value 205826048
Last sector, +sectors or +size{K,M,G} (205826048-488397167, default 488397167): +1G

Command (m for help): t
Partition number (1-4): 3
Hex code (type L to list codes): L

 0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris        
 1  FAT12           39  Plan 9          82  Linux swap / So c1  DRDOS/sec (FAT-
 2  XENIX root      3c  PartitionMagic  83  Linux           c4  DRDOS/sec (FAT-
 3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-
 4  FAT16 <32M      41  PPC PReP Boot   85  Linux extended  c7  Syrinx         
 5  Extended        42  SFS             86  NTFS volume set da  Non-FS data    
 6  FAT16           4d  QNX4.x          87  NTFS volume set db  CP/M / CTOS / .
 7  HPFS/NTFS       4e  QNX4.x 2nd part 88  Linux plaintext de  Dell Utility   
 8  AIX             4f  QNX4.x 3rd part 8e  Linux LVM       df  BootIt         
 9  AIX bootable    50  OnTrack DM      93  Amoeba          e1  DOS access     
 a  OS/2 Boot Manag 51  OnTrack DM6 Aux 94  Amoeba BBT      e3  DOS R/O        
 b  W95 FAT32       52  CP/M            9f  BSD/OS          e4  SpeedStor      
 c  W95 FAT32 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi eb  BeOS fs        
 e  W95 FAT16 (LBA) 54  OnTrackDM6      a5  FreeBSD         ee  GPT            
 f  W95 Ext'd (LBA) 55  EZ-Drive        a6  OpenBSD         ef  EFI (FAT-12/16/
10  OPUS            56  Golden Bow      a7  NeXTSTEP        f0  Linux/PA-RISC b
11  Hidden FAT12    5c  Priam Edisk     a8  Darwin UFS      f1  SpeedStor      
12  Compaq diagnost 61  SpeedStor       a9  NetBSD          f4  SpeedStor      
14  Hidden FAT16 <3 63  GNU HURD or Sys ab  Darwin boot     f2  DOS secondary  
16  Hidden FAT16    64  Novell Netware  af  HFS / HFS+      fb  VMware VMFS    
17  Hidden HPFS/NTF 65  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE 
18  AST SmartSleep  70  DiskSecure Mult b8  BSDI swap       fd  Linux raid auto
1b  Hidden W95 FAT3 75  PC/IX           bb  Boot Wizard hid fe  LANstep        
1c  Hidden W95 FAT3 80  Old Minix       be  Solaris boot    ff  BBT            
1e  Hidden W95 FAT1
Hex code (type L to list codes): 82
Changed system type of partition 3 to 82 (Linux swap / Solaris)

Command (m for help): p

Disk /dev/sda: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x7f3d8c0f

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048   205826047   102400000   8e  Linux LVM
/dev/sda3       205826048   207923199     1048576   82  Linux swap / Solaris

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 or after you run partprobe(8) or kpartx(8)
Syncing disks.

$ reboot 

After reboot we need to format the new swap partition.

$ mkswap /dev/sda3 
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=b28d9a2c-51a4-45e8-a0d3-d4b457afa359

Next step is to activating it.

$ swapon -a /dev/sda3

To verify/list current swap spaces.

$ swapon -s
Filename    Type  Size Used Priority
/dev/dm-0                               partition 4095992 0 -1
/dev/sda3                               partition 1048568 0 -2

To make this new swap space persistent, we need to add this new swap space to /etc/fstab.

$ blkid /dev/sda3 
/dev/sda3: UUID="b28d9a2c-51a4-45e8-a0d3-d4b457afa359" TYPE="swap"

$ vi /etc/fstab 

UUID=b28d9a2c-51a4-45e8-a0d3-d4b457afa359 swap                    swap    defaults        0 02

Reboot and verify that new swap space is active.

How to Remove a Swap Partition

First deactive it.

$ swapoff /dev/sda3

Verify it is no longer active.

$ swapon -s
Filename    Type  Size Used Priority
/dev/dm-0                               partition 4095992 0 -1

IF YOU HAVE ADDED IT TO /etc/fstab, DO NOT FORGET TO REMOVE IT FROM THERE AS WELL!