Linux command low level format

Warning!!! This command will destroy all data on your drive

This command is use to check bad sector on a hard disk.

dd if=/dev/zero of=/dev/sda1 bs=1024

Now we know that is a trouble at first 1 GB

How to check data chanel and info chanel (MikroTik + USB Modem / 3G Modem)

[admin@MikroTik] > /system serial-terminal usb2 channel=2

[Ctrl-A is the prefix key]


ATI
Manufacturer: Option N.V.
Model: GTM378
Revision: 2.3.3Hd (Date: Jul 17 2007, Time: 15:49:23)

OK

reference : http://wiki.mikrotik.com/wiki/Option_Globetrotter_HSDPA_USB_Modem

Windows server boot problem

I got this error after restore windows server 2008 using clonezilla. To fix it, boot to Windows Server 2008 DVD, enter command line, use this command :

bootrec /scanos

Bcdedit /export C:\BCDBkp

ren c:\boot\bcd bcd.old

Bootrec /rebuildbcd

Reference :

• https://www.youtube.com/watch?v=7e7FnRDRHus

Replacing hard disk on xenserver / linux software RAID

mark as failed disk :

    mdadm --manage /dev/md0 --fail /dev/sdb1 

remove the disk :

    mdadm --manage /dev/md0 --remove /dev/sdb1

change the physical drive, copy the partition, create the exact same partitioning as on/dev/sda :

    sfdisk -d /dev/sda | sfdisk /dev/sdb

add the new drive

    mdadm --manage /dev/md0 --add /dev/sdb1

done, check the progress :

    cat /etc/mdstat

references:

• https://www.howtoforge.com/replacing_hard_disks_in_a_raid1_array

Xenserver / linux software raid

I want my Storage Repository (SR) run under the software RAID (RAID1). My xenserver version 6.5. XenServer 6.5 do not load soft raid kernel modules on boot. To load soft raid manually run :

modprobe raid1

To load the soft raid module on boot, we can follow this steps : http://discussions.citrix.com/topic/360943-software-raid-mdadm-on-xenserver-65-unexpected-failure/?p=1855912

To build the RAID array :

 
mknod /dev/md1 b 9 1

mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

/dev/sdb1

and

/dev/sdc1

is using linux raid autodetect as the partition type. Use fdisk to create those partition.

To check the RAID building process :

cat /proc/mdstat

reference :

•  https://staff.ie.cuhk.edu.hk/~sfluk/wordpress/wp-content/uploads/2010/06/Software-RAID-on-XenServer.doc
• http://discussions.citrix.com/topic/360943-software-raid-mdadm-on-xenserver-65-unexpected-failure/?p=1855912

Internet access for android on vmware

If you download android x86 virtual appliance (http://www.osboxes.org/android-x86/) or installing android x86 manual to your vmware, you can give an internet access to the device

1. Add Network Adapter, with NAT as the network adapter type
2. Don't start your vm, edit the .vmx file, add / edit this line :

ethernet0.virtualDev = "vlance"

3. Now start your vm and you should can browsing from the android vm

reference:
https://lkubaski.wordpress.com/2012/08/15/running-android-on-vmware-player-with-networking-enabled/

Grails / GORM database mapping Money data type on Microsoft SQL Server

import java.math.BigDecimal
class Cloth {
    ...
    BigDecimal price
    ...
    static mapping = {
        price sqlType: "money"
    }
}

reference : https://msdn.microsoft.com/en-us/library/ms378878(v=sql.110).aspx
remember, grails is java too :D

Make uninitialized disk using diskpart

Warning this command will erase all of data on the disk!!!

1. run cmd
2. type : diskpart
3. type : list disk
4. select the disk you want to clean / uninitialize, in this example : select disk 1
5. clean
6. done

This steps are useful if we want to change the disk partition type (GPT or MBR or other)