I see in my company's IT installations that there are numerous disks with one partition occupying all of the space on disk. There is typically something like a
/dev/sdb with a partition
/dev/sdb1, and the size of
/dev/sdb1 is the size of the whole block device. The partition is then mounted with the required file-system format, mountpoint etc.
I do not understand why we would use a partition rather than the whole disk for such (1-partition) configurations. Is there any reason why a partition would be used in this case rather than a whole disk ? Are there any best practices that recommend this approach ?
For example, we could create a Filesystem on a whole raw block device and mount it without needing any partition:
mkfs.ext4 -E stride=16,stripe-width=64 /dev/xvde mount /dev/xvde /mnt/abc
That creates a mountpoint without a specified partition. As a verification:
# sfdisk -l /dev/xvde Disk /dev/xvde: 6527 cylinders, 255 heads, 63 sectors/track # fdisk -l /dev/xvde Disk /dev/xvde: 53.7 GB, 53687091200 bytes, 104857600 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
For something with a partition, we get the list of partitions under it:
# fdisk -l /dev/sdb Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes, 3907029168 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 label type: dos Disk identifier: 0x00082e8c Device Boot Start End Blocks Id System /dev/sdb1 2048 3907026943 1953512448 83 Linux
My fundamental question is this: Is there some advantage in creating a partition and then creating a filesystem on that partition, as compared to creating a filesystem on the whole disk and then mounting the whole disk ?