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SATA SSD vs SAS HDD - Which is faster?

 
Jonathan4
Occasional Contributor

SATA SSD vs SAS HDD - Which is faster?

Hi everybody, 

We have a Hyper-V server on site that has 3 x 1.2TB SAS HDD hard drives in a RAID 5. 

The software company has recommended that we "move our server VM on to SSD so that it will run faster". So I have identified SSD hard drives that are 240GB, which will be enough to host their server VM. 

My difficulty is that the SSD options are on the SATA interface and the drive transfer rate is half of the existing SAS HDD hard drives. 

 
SASvsSSD

 

Is there any point in me moving the server VM to these disks, will there be any performance advantage or am I making a big mistake?

16 REPLIES 16
KevinSpringPM
HPE Pro

Re: SATA SSD vs SAS HDD - Which is faster?

SATA SSDs are far far faster in general. Just because a sas hard drive has a 12gb link speed doesn't mean it's faster. The drive transfer rate in your image is just the hypothetical limit, not the actual transfer speed.

SATA SSDs are like a car driving 45-55 when the speed limit is 55

SAS HDDs are like a car driving 20 when the speed limit is 100

The sata SSD is still faster even though it's theoretical speed limit is lower. How that will benefit your specific application I can't really speculate on, but it can only help.

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SanjeevGoyal
HPE Pro

Re: SATA SSD vs SAS HDD - Which is faster?

Hello,

I hope all is well.

HDDs usually have more storage space, but SSDs are faster.

Both SSD SAS drives and SSD SATA drives are faster than their HDD counterparts.

They have the same characteristics though: SATA is still faster writing data, while SAS is faster at reading and writing data continuously.

 Please follow the below link for more clarification.

 https://store.hp.com/us/en/tech-takes/sas-vs-sata#:~:text=HDDs%20usually%20have%20more%20storage%20space%2C%20but%20SSDs%20are%20faster.&text=Both%20SSD%20SAS%20drives%20and,reading%20and%20writing%20data%20continuously.

 SSD performance for SAS and SATA

There are 2 main types of hard drives:

A hard disk drive looks a little bit like a record player. There’s an actuator arm that uses electromagnetism to write data onto a rotating platter. A solid-state drive has no moving parts and uses small chips to store data instead.

Which one is better? HDDs usually have more storage space, but SSDs are faster. An HDD must wait for the platter to rotate to the correct location before it reads or writes data. An SSD doesn’t have any moving parts that it needs to align, so its read/write speeds are uniformly faster [10].

Both SSD SAS drives and SSD SATA drives are faster than their HDD counterparts. They have the same characteristics though: SATA is still faster writing data, while SAS is faster at reading and writing data continuously.

SSD performance for SAS and SATA There are 2 main types of hard drives:

A hard disk drive looks a little bit like a record player. There’s an actuator arm that uses electromagnetism to write data onto a rotating platter. A solid-state drive has no moving parts and uses small chips to store data instead.

Which one is better? HDDs usually have more storage space, but SSDs are faster. An HDD must wait for the platter to rotate to the correct location before it reads or writes data. An SSD doesn’t have any moving parts that it needs to align, so its read/write speeds are uniformly faster [10].

Both SSD SAS drives and SSD SATA drives are faster than their HDD counterparts. They have the same characteristics though: SATA is still faster writing data, while SAS is faster at reading and writing data continuously.

 If you feel this was helpful please click the KUDOS! thumb below!   

Regards,


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Jonathan4
Occasional Contributor

Re: SATA SSD vs SAS HDD - Which is faster?

Hi there, 

Thank you for your posts. I think the first post gives me enough information to go back to the client with. 

It would be better if this information was very clearly available on the spec sheets for the drives. I'm not sure if that's possible in this case, but thanks for you help with this. 

regards, 

KevinSpringPM
HPE Pro

Re: SATA SSD vs SAS HDD - Which is faster?

Hi Johnathan,

This info is mostly available today in our quickspecs, where we list the read/write performance of each current SSD and HDD for you to compare. The specific drives you're looking for may be end of life so they aren't on the quickspecs anymore unfortunately, but you can find similar SSDs and HDDs to compare and see that the SATA SSDs have much higher performance across the board than the SAS HDDs do.

SSDs

HDDs


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JackWalsh
Occasional Visitor

Re: SATA SSD vs SAS HDD - Which is faster?

In simple terms, SAS & SATA are two technologies that enables transfer of data from motherboard to hard drives and vice versa. As far as usability is concerned SAS hard drives are usually preferred where higher data transfer rates are high, mostly in data centers and enterprise networks. Installing SAS HDD in a workstation and Servers helps in achieving higher performance while ensuring that the data transfer rates are optimal. Since servers can utilize multiple hard drives, there is no issue with the storage capacities & limitations of a singe sas hard drive. Comparatively SAS hard drives have lower data storage capacities but the tech enables its data transfer performance much higher than those in SATA. SATA hard drives are mainly a preferred option for desktop pcs, due to their high storage capacities. When it comes to SSDs & HDDs the SSDs (Solid State Drives) are much better & faster than HDDs (hard disk drives)

KevinSpringPM
HPE Pro

Re: SATA SSD vs SAS HDD - Which is faster?

Your reply is plagiarized from a 2011 blog post... Why? Not productive.

Source: https://www.turbotekcomputer.com/resources/small-business-it-blog/bid/57900/sata-vs-sas-what-is-the-difference

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krzysztoflaskow
Occasional Visitor

Re: SATA SSD vs SAS HDD - Which is faster?

sata ssd

kira12
Frequent Advisor

Re: SATA SSD vs SAS HDD - Which is faster?

Hi all,

HDD is limited with the spinning Disks Transferrate. SSD Cells are faster als the Interface Transferrate. SATA is limited by 6Gb/s, SAS is limited by 12Gb/s (if the Disk and Controller can handle the Speed) So you can see what Drive is faster.

best regards ré

P.S. i can show you Speedresults from 3,5"-HDDs, 6G-SATA and 12G-SAS Disks....

Interlink_Admin
Visitor

Re: SATA SSD vs SAS HDD - Which is faster?

Kira12,

What were the results of your speed tests? Based on what you said I got the impression you were saying the SATA SSD would be faster than the SAS HDD. Logically, I thought the same thing, but I happened to find myself in this situation and my speed tests revealed the opposite. Disclaimer - I am not the most knowledgable on this so I may be missing something obvious to explain my results.

I'm running an HP ProLiant ML350 Gen 9 server with a Smart Array P440ar controller. I have Windows Server 2016 booting to HP EG000300JWBHR 300 GB 10k RPM 12 Gbps SAS mechanical hard drives in RAID-1. One of these failed which prompted me to go down this path and test SAS mechanical hard drive versus SATA SSD. I had 2 spare Crucial MX300 SSD's which I thought would perform better than the SAS mechanical hard drives. My idea was to put the 2 Crucial MX300's into a RAID-1 logical drive and clone the boot drive to that. To test speed I put one of the Crucial SSDs into the ML350 server and created a RAID-0 logical drive to compare. Much to my surprise, the SAS mechanical drive blew away the SATA SSD. The results of my tests linked below.

SAS default profile results 
SAS real world profile results 
SSD default profile results 
SSD real world profile results 

I would appreciate anyone's insight or comments as to my results whether their experience has been the same or if I've done something incredibly stupid that would affect the results. Tests were run using Crystal DiskMark CrystalDiskMark – Crystal Dew World (crystalmark.info)