How to Check Harddrive information
Here are several commands that will allow us to check information regarding hard drives.
fdisk: for hdd sizes/partitions
fdisk is useful for checking the sizes and partitions of hard drives that are connected to a host. Physical hard disks are usually given a name of /dev/sd[a-z]. Using the command as root:
fdisk -l
will provide us information regarding all the physical hard disks that are located on the host and all the partitions that reside on those disks. Non-physical disks are included in the output too.
You will see devices such as:
Disk /dev/sdc // physical hard disk Disk /dev/md[0-10] // software raid volume Disk /dev/mapper/vg_system-lv_root // logical volume
cat /proc/scsi/scsi for actual models of HDDs
We have a variety of different HDD models we use from various companies. We'll often encounter an HDD we find to be reliable or a model we want to avoid altogether for the rest of our lives. Since
we don't always have physical access to the interior of a machine to check the HDD models, the easiest way to check what model is in a host is to check under /proc/scsi/scsi.
[root@he bulk]# cat /proc/scsi/scsi Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: Samsung SSD 840 Rev: BB6Q Type: Direct-Access ANSI SCSI revision: 05 Host: scsi1 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: Samsung SSD 840 Rev: BB6Q Type: Direct-Access ANSI SCSI revision: 05 Host: scsi2 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: WDC WD1000CHTZ-0 Rev: 6A01 Type: Direct-Access ANSI SCSI revision: 05 Host: scsi3 Channel: 00 Id: 00 Lun: 00 Vendor: ATA Model: WDC WD1000CHTZ-0 Rev: 6A01 Type: Direct-Access ANSI SCSI revision: 05
cat /sys/block/sd*/queue/rotational check if HDD/SSD
If you're not sure whether the disks on your system are HDDs or SSDs, do the simple command:
cat /sys/block/sd*/queue/rotational
The output is in descending order starting from the first disk detected, usually sda.
This will output either 0 or 1.
0 == SSDs 1 == HDDs
Example:
# My first disk is an SSD [root@he fast]# cat /sys/block/sda/queue/rotational 0
# I have two SSDs, /dev/sda & /dev/sdb, and two HDDs /dev/sdc & /dev/sdd [root@he fast]# cat /sys/block/sd*/queue/rotational 0 0 1 1