Why does Linux say my Linode's drives are HDD?
Linode
Linode Staff
Linode's pricing page says each Linode is powered by SSD storage, but lsblk shows each disk as rotational=1 (i.e. a spinning disk drive, not solid state):
$ lsblk -d -o name,rota
NAME ROTA
sda 1
sdb 1
Are my Linodes actually running on solid state drives?
2 Replies
This is a consequence of virtual hosting. Our hosts divvy up resources using KVM, which creates virtual drives that Linodes utilize. I checked my own Linode and can see the disks are of model QEMU HARDDISK:
> cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: QEMU Model: QEMU HARDDISK Rev: 2.5+
Type: Direct-Access ANSI SCSI revision: 05
Host: scsi0 Channel: 00 Id: 01 Lun: 02
Vendor: QEMU Model: QEMU HARDDISK Rev: 2.5+
Type: Direct-Access ANSI SCSI revision: 05
If you want to confirm without a doubt that your Linode is powered by SSDs, use dd to test the write speed. Try the following command, with which I've included my own output (the sync command is used to clear the cache before testing):
$ sync; dd if=/dev/zero of=speedtest.txt bs=1M count=1024; rm speedtest.txt
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 1.12886 s, 951 MB/s
An additional tool to check read/write speeds is hdparm but isn't usually installed by default. Additionally, this StackExchange post has more discussion on this topic.
Hi,
I had the same question. Here is another tool
http://woshub.com/check-disk-performance-iops-latency-linux/
called fio
D