Will speeds be better when SATA HDDs are connected to low-cost SAS controllers?
I am using the PERC H200, a low-cost controller that connects SAS HDDs.
It is an old model, and specs are not so different from what is popular.
I don't have a cache. I just bought it for a SAS HDD connection I bought by mistake.
In fact, the term entry-level SAS itself is a contradiction. If you are an entry-level, you can just buy a cheaper SATA.
The SAS HDD I am currently using is HGST 4GB, 7200rpm.
I tried to add a hard drive here and I bought SATA properly. Just for backup.
However, this SATA HDD is not the SATA controller of the board,
I was wondering if connecting to a SAS controller would have the benefit of speed.
The SATA HDD used in the test is WD Purple 2GB, 5400 rpm.
Test 1. Continuous read and write test
The data below shows the speed depending on how the controller is connected.
SATA: Connect the SATA HDD to the SATA port of the mainboard (general SATA HDD connection)
SAS: Connect SATA HDD to SAS terminal of SAS controller
SAS-raid1: Connects two SATA HDDs to SAS terminal of SAS controller and binds raid1 to
HGST (SAS): Connect SAS HDD to SAS terminal of SAS controller (Connecting SAS HDD currently in use)
Observation 1: Changing from a SATA connection to a SAS connection is unchanged.
Observation 2: Two HDDs are bundled with raid1, which is about 1/2 of the speed of single use.
Observation 3: The high speed of HGST (SAS) seems to be due to higher rpm than the connection method. (5400 => 7200)
Conclusion: The speed of SATA HDD does not change greatly depending on the connection method. Just decide on the HDD spec.
Test 2. Random Read and Write Test
Random read / write rather than continuous under the same conditions as above test.
This is not much different from the above results.
However, when bundled with raid1, the write speed is reduced to less than 1/2.
Conclusion: HDD speed is largely determined by HDD performance.
Reference:
(1) The result can be different for high-priced SAS controllers with cache.
(2) I just benchmarked the speed here, not stability or any other performance.
(3) The use of SAS HDD by general users does not mean much. Do not buy it by mistake. Like me.