Localizar tamanho do cluster

4

Estou executando o Ubuntu 11.04 e estou querendo saber como encontrar o tamanho do tamanho da unidade de alocação? Existe um comando no Ubuntu para encontrar isso? Além disso, dependendo do tamanho da unidade de alocação, a quantidade total de espaço no disco rígido utilizou uma alteração de arquivo? Verifiquei os tamanhos dos arquivos usando ls e du -b e, em ambos os casos, estou obtendo os mesmos valores.

Incluindo dados:

 sudo tune2fs -l <file system> 
  Block count:              8052736
  Reserved block count:     402636
  Free blocks:              2797402
  First block:              0
  Block size:               4096
  Reserved GDT blocks:      1022
  Blocks per group:         32768
   Inode blocks per group:   512
  Flex block group size:    16
  Reserved blocks uid:      0 (user root)
  Reserved blocks gid:      0 (group root)
  Journal backup:           inode blocks

Portanto, se o tamanho do bloco for 4096 bytes, os arquivos menores que 4096 ocupam 4096 bytes de armazenamento no disco rígido. E quanto aos arquivos com mais de 4096 bytes quanto espaço eles ocupam? Existe um comando para encontrar o mesmo?

    
por bhavs 15.03.2012 / 15:29

1 resposta

5

Top post editar:
Encontre o tamanho de forma preventiva:

temp = int(size/block)  
if mod(size/block) != 0:  
    temp += 1
temp = temp*block
print temp

para saber quantos blocos um arquivo tem no disco:

ls -s

em que tamanho do bloco é o tamanho do bloco de partição
e tamanho no disco é tamanho de bloco * número de blocos

Explicação sobre diferenças de terminologia de tamanho de bloco
sudo fdisk -l /dev/sda
onde / dev / sda é o disco rígido em questão

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 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: 0x000c1f6b

Device Boot Start End Blocks Id System /dev/sda1 * 63 498014 248976 83 Linux /dev/sda2 498015 976768064 488135025 5 Extended /dev/sda5 498078 976768064 488134993+ 83 Linux

Isso lhe diz várias coisas. Alguém já disse melhor assim blockquote:
The problem with this is that there are four distinct units that you must be keeping in 
mind. To make things even worse, two of these units bear the same name. These are the 
different units:

1. Hardware block size, "sector size"
2. Filesystem block size, "block size"
3. Kernel buffer cache block size, "block size"
4. Partition table block size, "cylinder size"

To differentiate between the filesystem block size and the buffer cache block size, I 
will follow FAT terminology and use "cluster size" for the filesystem block size.


The sector size is the units that the hardware deals with. This ranges between different 
hardware types, but most PC-style hardware (floppies, IDE disks, etc.) use 512 byte 
sectors.

The cluster size is the allocation unit that the filesystem uses, and is what causes 
fragmentation - I'm sure you know about that. On a moderately sized ext3 filesystem, 
this is usually 4096 bytes, but you can check that with dumpe2fs. Remember that these 
are also usually called "blocks", only that I refer to them as clusters here.

The cluster size is what gets returned in st_blksize in the stat buffer, in order for 
programs to be able to calculate the actual disk usage of a file.

The block size is the size of the buffers that the kernel uses internally when it caches 
sectors that have been read from storage devices (hence the name "block device"). Since 
this is the most primitive form of storage in the kernel, all filesystem cluster sizes 
must be multiples of this. This block size is also what is almost always referred to by 
userspace programs. For example, when you run "du" without the -h or -H options, it will 
return how many of these blocks a file takes up. df will also report sizes in these 
blocks, the "Blocks" column in the fdisk -l output is of this type, and so on. It is 
what is most commonly referred to as a "block". Two disk sectors fit into each block.


The cylinder size is only used in the partition table and by the BIOS (and the BIOS 
isn't used by Linux).

"df" only operates on filesystems, so, no, it can't be used without a filesystem - 
without a filesystem, the data that it would return doesn't exist. "du" operates on 
individual files. 

de aqui .

    
por RobotHumans 15.03.2012 / 15:45