Analyse this fdisk -l


 
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# 1  
Analyse this fdisk -l

Hi,

Someone please analyse the following o/p of fdisk -l and tell me what it means for /dev/sda, /dev/sdb, /dev/sdc ....


Code:
Disk /dev/sda: 53.6 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         131     1052226   83  Linux
/dev/sda2             132        2239    16932510   82  Linux swap / Solaris
/dev/sda3            2240        6527    34443360   8e  Linux LVM

Disk /dev/sdb: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes


Disk /dev/sdc: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes


Disk /dev/sdf: 289.9 GB, 289910292480 bytes
Disk /dev/sdh doesn't contain a valid partition table
Disk /dev/sdi doesn't contain a valid partition table
Disk /dev/sdj doesn't contain a valid partition table
Disk /dev/sdk doesn't contain a valid partition table
255 heads, 63 sectors/track, 35246 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes


Last edited by Scott; 10-24-2012 at 06:33 AM.. Reason: Code tags, not quote tags
# 2  
Since I am not a linux admin, I will give you the point of vue of a pure unix admin..
looks like a disk physically partitionned in 3 not fully LVM compliant (like HP-UX 9...) and so would see one file system for booting the second for swap and the third (all the disk left), dedicated to LVM (this is about /dev/sda*...)
It is difficult to say more since we have no idea what hardware is installed...
# 3  
hi,


you have several disks on your box:


1 - /dev/sda: 53.6 GB, 53687091200 bytes
1,1 - first partition of this disk /dev/sda
/dev/sda1 *
the star mean that is your boot partition

1,2 - second partition of /dev/sda
/dev/sda2

ect ....

2 - /dev/sdb: 536.8 GB, 536870912000 bytes
3 - /dev/sdc: 536.8 GB, 536870912000 bytes
...

5 - /dev/sdh or i or j ork are not partitioned
# 4  
Quote:
Originally Posted by stunn3r
Code:
Disk /dev/sda: 53.6 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Short introduction to disks:

A "hard disk" is (classically - the logic is still used even if it doesn't look like that any more) a stack of rotating platters mounted on a common spindle. On these platters there are concentric rings ("tracks") of magnetic coating. These concentric rings are divided in "sectors".

As the spindle is rotating a device goes in between the platters which looks like a comb, carrying a read/write head on every tip.

The output now tells you the geometry of this disk - at least, as it is told by the disk device to the controller: it has 255 heads, meaning there are are 128 such platters. (Every platter has a lower and an upper side to read from and has 2 [read-write-] heads therefore.)

There are 6527 concentric tracks (=cylinders) on every disk. Because the corresponding tracks on all the platters build a logical unit it is easy to see why this is called a "cylinder".

Lastly, every such track is divided into 63 sectors. Note that sectors occupy a certain angle rather than a certain area of magnetic material. The inner sectors are therefore shorter than the outer sectors, but still can carry the same amount of data. This is the reason why every track is divided into the same number of sectors.


Quote:
Originally Posted by stunn3r
Code:
Disk /dev/sda: 53.6 GB, 53687091200 bytes

This is the disk device itself. "/dev/sda" means the whole disk, while "/dev/sda<n>" means "a certain partition number <n> on /dev/sda"

Quote:
Originally Posted by stunn3r
Code:
   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         131     1052226   83  Linux
/dev/sda2             132        2239    16932510   82  Linux swap / Solaris
/dev/sda3            2240        6527    34443360   8e  Linux LVM

The partition table layout for the first disk. Probably this is a Linux system disk and Linux can't boot from LVM volumes. Therefore a single partition "/dev/sda1" to boot from, probably mounted at "/boot" and containing the boot loader (Grub?). Than a partition "/dev/sda2", which contains a swap partition. It is possible to have swap partitions inside the LVM, but some Linux admins hold that it is better to have the swap outside LVM too. Finally a LVM partition, which contains all the other volumes/filesystems there are in the system.



Quote:
Originally Posted by stunn3r
Code:
Disk /dev/sdb: 536.8 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

The second disk /dev/sdb. It seems not to carry any partitions at all yet. Similar for all the other disks in your system.

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
# 5  
Quote:

I hope this helps.

bakunin
Yes, That was really helpful Smilie .. Thanks Smilie

can you also tell me what are these two:

Quote:
Disk /dev/sdf: 289.9 GB, 289910292480 bytes
Disk /dev/sdh doesn't contain a valid partition table
# 6  
Quote:
Originally Posted by stunn3r
can you also tell me what are these two:
Code:
Disk /dev/sdf: 289.9 GB, 289910292480 bytes
Disk /dev/sdh doesn't contain a valid partition table

The disk "/dev/sdf" has a size of 290GB, that part should be obvious.

The other disk "/dev/sdh" was not yet partitioned. A disk drive has to be written with some low-level information prior to be used by an operating system. This is the "partitioning" first, which divides the disk in one or more logical "disks" - partitions. Only after partitioning these logical disks can be used to store filesystems on them. Storing the file system information is called "formatting".

Think of a disk like a bare storage room: to actually store something in it you first have to build some shelves, on which to store the goods you want to store, probably prepare a list where you can enter all the things you stored and the place they are at to find them again, etc.. Formatting is like building these shelves and the list. It is preparing the storage room for actually storing goods there.

I hope this helps.

bakunin
This User Gave Thanks to bakunin For This Post:
 

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