For this month I have rented two vServer, each from a different provider. Both indicated that the disks of the system use SSD technology (making me expect a bandwidth of at least 300MB/s and maybe more, as I know from experience in my laptop).
ssh
'ing into the machines I found one to be rather sluggish with a task that requires rather more disk IO. I hence want to
ask here how I could go about to benchmark if the advertised thing (having a SSD disk space) is indeed true.
I attempted
dd if=/dev/rootFssBlockDev bs=5M count=2000 of=/dev/null
and receveive those outputs.
hoster 1 (85.2MB/s)
dd if=/dev/rootFssBlockDev bs=5M count=2000 of=/dev/null
2000+0 records in
2000+0 records out
10485760000 bytes (10 GB, 9.8 GiB) copied, 123.05 s, 85.2 MB/s
hoster 2 (544 MB/s)
dd if=/dev/rootFssBlockDev bs=5M count=2000 of=/dev/null
2000+0 records in
2000+0 records out
10485760000 bytes (10 GB, 9.8 GiB) copied, 19.2678 s, 544 MB/s
To me the values benchmarked on host1 "smell" like they attempt to sell a HDD for an SSD (I actually feel kinda tricked). However this question seeks insight how else, I could confirm my assumption and hence test/benchmark that the offered machine (vServer) indeed inlcudes SSD disks.
Update
list of tools I also used for benchmarking (yielding similar results)
hdparm -t /rootFssBlockDev
fio
(as suggested in this answer)
Maybe there is an answer that would provide an insight into the aspect that a key difference between HDD(platters) and SSD(flash) is the access speed in random access reads.
Since the answer of Michael Hampton suggests that there might be a slight possibility the poor performance would be from congestion, contested access from more virtual hosts sharing the same SSD. It appears to me that even in such a case there should be little further decline of access speed originating from the not sequential read, but random access read. Bottom line, is it not possible to infere SSD vs HDD from the characteristic decline in speed between sequential and random reads?
Update (fio results)
Here the results of the fio tool, showing stark contrast in random and sequential reading speed (while both seem low considering the SSD claim)
randread: (groupid=0, jobs=1): err= 0: pid=3593: Sat Sep 28 11:27:22 2019
read: IOPS=229, BW=917KiB/s (939kB/s)(256MiB/286009msec)
seqread: (groupid=0, jobs=1): err= 0: pid=3635: Sat Sep 28 11:27:22 2019
read: IOPS=3855, BW=15.1MiB/s (15.8MB/s)(1024MiB/67998msec)