I searched and found 2 options, none of which I'm confident provided me the answer.
1: cat /sys/block/sda/queue/rotational
This output '1' to stdout. What does this mean?
2: lshw -class disc
but couldn't find anything that answers my question.
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Is this a VPS or bare metal?– David SchwartzNov 7, 2013 at 19:06
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its VPS and i have root access– Amir BarNov 7, 2013 at 19:07
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5The honor system.– MDMoore313Nov 7, 2013 at 19:16
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3@MDMoore313: Exactly. Quite frankly, if I had reason to even suspect my hoster would try to fool me like that, I would switch away immediately.– SvenNov 7, 2013 at 19:36
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This is not a technical problem...– ewwhiteDec 25, 2013 at 13:23
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2 Answers
Let's try to read 1000 random 4k blocks from first 16GB of a disk:
time for i in `seq 1 1000`; do
dd bs=4k if=/dev/sda count=1 skip=$(( $RANDOM * 128 )) >/dev/null 2>&1;
done
This is something that should be very slow on rotating drive in comparison with SSD. On my desktop class SSD it ends in about a second. On desktop class 7200rpm rotating drive it ends in 10 seconds.
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thank I got these respone:
real 0m1.632s user 0m0.336s sys 0m0.939sit mean i am on ssd?– Amir BarNov 8, 2013 at 8:37 -
1
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on my VM whose virtual disk is placed on an HDD it takes only ~1.5s to complete this so it's not correct– phuclvDec 6, 2016 at 2:27
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1You might need to make sure that you have data there. Unused space on a VM volume might be using sparse files or equivalent technology - that would fool this check. Also if there are like 10+ drives in RAID behind this, which would share load, then it's not that easy to distinguish it from single SSD.– TometzkyDec 7, 2016 at 17:16
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That hides all errors :D So you can measure error reporting time:
dd: failed to open ‘/dev/sdb’: Permission deniedApr 20, 2020 at 7:13
In a physical machine (not a VPS), you can get the type with smartctl:
smartctl -a /dev/sda
and grep for Rotation:
smartctl -a /dev/sda | grep Rotation
Rotation Rate: Solid State Device
smartctl -a /dev/sdb | grep Rotation
Rotation Rate: 5400 rpm
It's quite likely you have no chance to identify the disk type inside a VPS, as the hypervisor abstracts the real hardware away from the guest machines.
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there is nothing i can install for exmaple that will check the write speed or something? becuose i am afraid that he gave me normal hd when he promised for ssd– Amir BarNov 7, 2013 at 19:15
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2It's somewhat difficult inside a VPS because there are many factors affecting the disk speed, but at least the access times should be significantly better with a SSD as compared to normal disks. Try
bonnie++etc.– SvenNov 7, 2013 at 19:29 -
3@amirbar you have to remember also that your VPS could be distributed amongst several drives and/or CPUs, I wouldn't worry too much about physical hardware as I would actual performance of the service you're trying to run on the VPS. SSDs are nice but not necessarily a requirement for most services. Nov 7, 2013 at 19:33