Sas ssd vs sata ssd

ehsdav

Distinguished
Jul 17, 2011
4
0
18,510
Hello,
what is difference between "sas ssd" vs "sata ssd"?
performance, typical and max read and write speeds , and ...
which one is better for speed i
 
Solution
Well, now you've opened a can of worms. Using SSDs in RAID is what I call a "religious question." People will argue these points at great length but no-one will get to a conclusion. The arguments against RAIDing SSDs are 1) using RAID cuts off the TRIM command, so drive performance will degrade over time, and 2) If you buy the twice-the-size drive in the same product line, the manufacturer will be using twice the channels anyway, so RAID0 is not only risky but pointless. Against point 1, people now argue that Garbage Collection is good enough to be sufficient.

The answer to any good question depends on the conditions. In the abstract, SAS is "better" than SATA. In context, I don't use SAS. It's designed for server...
If anyone makes an SAS SSD, that means that it uses the Serial Attached SCSI interface instead of the SATA interface.

Hobbyist and mainstream motherboards have SATA ports. Some higher-level server hardware uses the SAS interface. Look up SAS on Wikipedia.
 

ehsdav

Distinguished
Jul 17, 2011
4
0
18,510


Thanx.
I know difference of interface. But i want to know which configuration is better.
connecting "sata ssd" to sata port of motherboard OR "sas ssd" to sas port of motherboard OR "sata ssd" to sas port of motherboard.
Is the raid configuration of sas better than sata (for speed concern and bottleneck limits) for example?
If yes raiding with sas ssd s is better or raiding with sata ssd s which is connected to sas ports of motherboard.
 
Well, now you've opened a can of worms. Using SSDs in RAID is what I call a "religious question." People will argue these points at great length but no-one will get to a conclusion. The arguments against RAIDing SSDs are 1) using RAID cuts off the TRIM command, so drive performance will degrade over time, and 2) If you buy the twice-the-size drive in the same product line, the manufacturer will be using twice the channels anyway, so RAID0 is not only risky but pointless. Against point 1, people now argue that Garbage Collection is good enough to be sufficient.

The answer to any good question depends on the conditions. In the abstract, SAS is "better" than SATA. In context, I don't use SAS. It's designed for server environments, with the major points that I am aware of being dual-porting, which allows the drive to fail over to another server if the primary goes down, and the huge number of devices that can be attached to a single port.

In practice, whether or not SAS is better for you depends on your application. I am not aware of any advantage of SAS in the home / hobbyist world, and it adds a significant expense. My personal take is that there is no advantage to SAS in my hobbyist world, considering that I am not building (as some hobbyists do) a cluster or server. And I do have SCSI devices; there is an Ultra-320 SCSI controller in my PC right now, to connect to my RAID array.

So the main question is: What exactly are you building, and what will it / they be used for? And my question, out of curiosity, is: What motherboard have you got that has both SATA and SAS ports? Or are you at the pre-buying stage?
 
Solution

ehsdav

Distinguished
Jul 17, 2011
4
0
18,510


Hi
Sorry for late and thanx for your time.
i am using hp dl 380 g7 server. in such servers that has sas/sata controller i can use both of them.
my main question is now just for my knowledge. it is just difference between connectors or sas standard and commands has advantage over sata in raiding ssd advantage
I bought sata ssd of A-DATA. but although this server recognize it and i could install OS on it but server cant get thermal information of hdd so it beeps and all fns go at soundy high speed.

At last thanx and sorry for your time.
 

Joscon5

Distinguished
Jan 9, 2012
1
0
18,510
On the plus side, you've answered questions for all the future generations of Googlers who have come here to answer their questions of the benefits of SAS. Thanks!
 

toddbailey

Distinguished
Oct 21, 2006
34
0
18,530
My 2 cents, SAS devices are made to higher standards, typically for 24x7 environments. In the hdd world many sas drives spin at 10K or 15K rpm, in the sata world 7200 is common. The higher spin rate gives faster access times to the data.
On my hp workstation, it has both sas and sata, For amusement, I benchmarked a 3.5 inch 7200 rpm sata drive against a 2.5 inch 10k rpm sas drive. The sas drive had the faster access time 6ms versus 14ms but data transfer rates were about the same, roughly 60 mb/s My next benchmark had 2 3.5 inch 15K sas drives in raid 1, access times remained about 6ms but data transfer rates shot up to around 235 mb/s. Another benchmark I ran was 4 7200 rpm 2 tb sata drives in raid 5, access times were around 14-15 ms and transfer rates in the low 200 mb/s.
My last benchmark was a single sata ssd ( a 36 gb torqx II from patriot)
access time fell to .7 ms with data transfer rates around 240 mb/s.

Whats the better device? I'll take sas with it's 5 year hdwr failure guarantee and a 1.4 mill hr mtbf over sata, for small capacity storage, since finding 2 tb sas drives will cost a pretty penny. Sata is good for large capacity over slightly lower performance.

I'm using a pair of 73 gb raid 1 drives for OS and database use and sata for raw storage capacity.
 

petar

Distinguished
May 16, 2004
37
1
18,535
Sorry for posting on an such old thread. For the sake of new readers who seek answers; and have not yet found their way; here's short reply based on my experience. SAS controllers can sustain speed of 500 MB reading on e.g. 4 SSD drives simultaneously, while intel or amd chipset have no chance of delivering speeds like that on simultaneous access. That's huge difference, so SAS controller YES.

Downside I experienced with Windows 7 x64 (and probably server windows would have same issue) is LSI drivers for windows which do not pass SMART, SLEEP, TRIM commands natively. There's SATL (L=Layer), google for SAS SATL SSD to see further issues with TRIM with SAS on SATA SSDs. LSI seems to address the issue but at least not working on windows; maybe Liunx hdparm can do something.
 

Matty B

Reputable
Jun 7, 2014
1
0
4,510
"I bought sata ssd of A-DATA. but although this server recognize it and i could install OS on it but server cant get thermal information of hdd so it beeps and all fns go at soundy high speed."

I've had 8 midline drives, which are sata, along side 4 sas drives. in the same server you have, never had a problem with fan speeds or beeping.

but this is from the hp site. "Yes, the system supports both SAS and SATA disks. The only restriction is you cannot mix drive types in an array." that could be the reason for your beeping. if you have sff drives in your 380, each cage has two cables. thus 4 drives per cable. I cant quote or link where I read this. but I seem to recall something about if one drive outta the group is sata, then that forces all other disks to run at sata speeds. thus why they can don't mix drive types. that problem may have been fixed in firmware updates.

does the drive have thermal sensors onboard ?

if you are not running this drive in a raid setup. you can get a PCI-X card that mounts a sata ssd if you have a free pci-x slot. this would mean those annoying beeps and fans running flat out would be avoided. an possibly faster performance.


btw, the differences in the connectors themselves.
when you look at the connectors of sas vs sata. sata has data and power separated, sas they are one plug, the gap is filled with a extra 4-5 pins. now don't ask me what those pins are for. as im not totally sure, I recall its something about sending out info about drive position, drive condition and led sled lights - don't quote me on this. these extra pins are why why you can put a sata into sas but not sas into sata.

not being sure what you are using this drive for. if its possible I would suggest pci-x card mounting it. its just a hp io expander then, with out the price tag.
 

Blacky13o7

Reputable
Mar 11, 2015
1
0
4,510


I do quote you on this, excuse me please. As far as I know, this is not true. I've read, that those pins basically deliver the same information as the logic pins, enabling to have a drive set up in two different controllers or even servers. This provides a certain redundancy if controller 1 or server 1 passes out.
I apparently do not have a quote for that since I read it in a german forum and can't find the post anymore, on the other hand, I guess you guys wouldn't understand german. I hope I could help.
 

petar

Distinguished
May 16, 2004
37
1
18,535
Oh well, it's an old post but anyway -- SLEEP and power management started to work after resintalling windows and providing all new drivers. I crossflashed IBM to LSI SAS HBA and god knows what else I have changed - but after all that drives sleep well and TRIM works perfectly. In the mean while I got better LSIs which do hardware RAID 5.