SATA faster than SSD ???
I installed vmware ESXi 6.5 on my server, and I tested it with SATA and SSD. I created 2 datastore ( 1 for SATA and 1 for SSD ). I did a writing speedtest on a CentOS VM and the results are:
ON SATA: 377 MB/s
ON SSD: 243 MB/s
How could be possible ?
Could be SSHD, could be another SSD, could be a RAID set up. Or it could juist be the size of the write test. hard to say. I assume when you say sata you mean HDD.

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what number the SSD should be there?
I mean HDD.
I used 2xHDD in RAID1 and 2xSSD in RAID1

I mean HDD.
I used 2xHDD in RAID1 and 2xSSD in RAID1
What brand is the SSD and what model is your server?
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Is a HP Generation 6 ( I do not know the model exactly  )
The SSD is ADATA.

Not all SSD are created alike. Some perform better than others.
I don't know anything about 'ADATA' but the biggest thing with SSD over SATA is not throughput but seek time / random read/write.
If you're just reading and writing large files sequentially SATA will work fine. If you're serving hundreds or thousands of requests per second and they're all small requests from all over the storage - SSD will win any day of the week hands down.
 
SenseiSteve (03-06-2018), ughosting (03-07-2018)
Post the models of the SSD and HDD, then you can look for the IOPS. But most SSD (even the cheapest) should be faster than a HDD

I am using both of them SSD and SATA but i got some different result other than yours, and i can say SSD is too faster than SATA .
Are you using same data copying on both of them storage?
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Make sure it is true SSD and not SSHD.
Also check the type of ssd, some can have low write speeds...they vary a lot between models and manufacturers.
Where SSD wins is in processing multiple files at ones, the seek times are incredible as there is moving parts.
They are great for running websites, whereas SATA is good for backups and storing large files for eg
Usually sata and ssd are using the same interface and you should get the same speed, or better for ssd. SSD's are not necessarily faster as interface, but you get faster response & seek time and a lot more IOPS. However, there are controllers that differentiate the SATA and SATA SSD, and they set Sata to 3Gbps and Sata SSD to 1.5, but it doesn't seem to be your case. Probably you have a write cache active for sata but not for ssd, you can try activating/deactivating with HDPARM
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As virtono said , what matter the most is the controller. I ve seen in a gmaing computer an SSD being defeated by an HDD. Probably the controller slows down the SSD which is a result of having the cache enabled for the HDD

As MikeDVB said
Quote:
If you're serving hundreds or thousands of requests per second and they're all small requests from all over the storage - SSD will win any day of the week hands down.
Check out the attached comparison.
Attached Images
File Type: png	Comparison of HDD to SSD to NVMe.png (28.1 KB, 5 views)
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I would prefer to have SSD all the time.
Artashes
HD Management Staff
@SenseiSteve, that Samsung 960 NVMe looks yummy.