4U Supermicro Storage Expander 3.5" 45 Bay Server JBOD CSE-PTJBOD-CB2

[ttabbal]

I'm guessing with years of use the answer has to be yes, but for completeness... Those with SATA drives on SAS expanders, have you had single drive failures that did not cause other problems? What kind? I'd expect bad sectors to be fine, but non-responding drives to be an issue if it's an issue at all.

I could maybe see a problem with old SAS1 stuff, but it seems like things have stabilized a lot since then.

 

[Black Ninja]

The gripe is with the expander backplane

See SATA drives behind expander still a no-go? for another recent discussion around this

Great info. Thanks for the link. This is what I was trying to bring people's attention to.

 

[Black Ninja]

By the way I would love to be wrong on this one. You can't imagine how much I would like to get an jbod chassis with 36 or more bays expander and get all my sata drives connected.

 

[CyberSkulls]

There is nothing in that thread that should scare you off or keep you from adding a 36 bay JBOD.

The high points from that thread is that SAS1 is limited to 2TB drives. Anything above that may or may not work. That goes for the expander backplanes as well as SAS cards, raid.. HBA.. This is a limitation in the chipset and when people try to run drives over 2TB things can get hairy. An example is I have some SAS1 backplanes in a SM 846 that will in fact accept drives over 2TB. I can populate it with 23, but not 24 and it will run. Would I run it like that? Absolutely not as I'm playing with Fire at that point. Not because it is flaky or a SATA drive in a SAS environment but because I'm exceeding the design limits and running on borrowed time.

The next item of interest is the mention of WD green drives in a ZFS environment. Those drives didn't have TLER to my knowledge and could drop out of the array causing a degraded state. Again, not a SATA drive in a SAS environment, it's a drive issue with people running a specific drive in a environment (raid array) that it wasn't designed for. Again, people playing with fire.

So the above two issues are 100% self inflicted by the user and are in no way a result of using SATA drives in a SAS environment.


Sent from my iPhone using Tapatalk

 

[Rand__]

Most of the info I have found and my personal inhibitions base on are from this thread:
ZFS and SAS expanders with SATA drives a toxic combo?

There are some others cross-referencing themselves, some just mentioning the issue, some with some details.
SATA in SAS JBODs bad idea...
The ZFS NAS Box Thread - Ars Technica OpenForum
/dev/dump: Why SAS->SATA is not such a great idea
Skupiny Google

I don't think there will be a definite answer. It used to be a bad idea in earlier times but either nobody does it any more (i doubt that) or the issues have reduced due to improved performance of sata drives, compatibility/firmware or whatever.

In the end it's as always - get proper backups

 

[i386]

SAS1 (introduced 2004, that was the time with single core prescott pentium 4 hitting 90°c easilly and the "xbox huge" original xbox) expanders from LSI (and other vendors) came without an option to update the firmware. You were stuck with the sometimes buggy firmware that the vendors flashed on the chip and shipped to the oems.
@CyberSkulls has probably a sas1 expander backplane that came with one of the latest firmware versions that support 2+ tb drives.

2008 and with the launch of sas2 products LSI offered an sdk to develop/customize the firmware for the expander.

 

[nk215]

I have 4tb SAS drives and 2TB SATA drives connected to my SAS1 backplane and they work fine. I only have 6 drives total however.

I am on a look out for a 846A backplane in a good price range w/o much luck. Since I don't need the hot-plug feature and only use a handfull of HDD, I may as well remove the backplane and directly plug the cable onto the drive directly if issue arrives.

 

[croakz]

Seems weird to say SATA drives aren't reliable on a SAS expander. A lot of the big guys, like Dell EMC, use SAS expanders and SATA drives.

 

[Black Ninja]

Seems weird to say SATA drives aren't reliable on a SAS expander. A lot of the big guys, like Dell EMC, use SAS expanders and SATA drives.

Have you read the info above ?

 

[croakz]

Have you read the info above ?

Yeah, seemed like a lot of non-professional FUD.

 

[Black Ninja]

Yeah, seemed like a lot of non-professional FUD.

Professional ? and using the cheap consumer sata drivers with sas expanders is far from professional. Even using sas drives not approved and tested is from the list is not professional. I guess it all comes down to what you ultimate goals is and then the means to achieve it.

 

[Evan]

What @croakz is saying is what I said, that a lot of the bigger vendors doing it without issue.
I agree about the FUD somewhat and that is that yes some people had issues related to green drives without TLR or whatever SAS1 issues but SATA drives behind SAS expanders itself is not likely an issue.

 

[Black Ninja]

What @croakz is saying is what I said, that a lot of the bigger vendors doing it without issue.
I agree about the FUD somewhat and that is that yes some people had issues related to green drives without TLR or whatever SAS1 issues but SATA drives behind SAS expanders itself is not likely an issue.

Respectfuly I disagree with you on everything. I mean about the vendors doing that and about your green drives statement.

 

[croakz]

Respectfuly I disagree with you on everything. I mean about the vendors doing that and about your green drives statement.

Seems strange that you disagree. EMC has shipped hundreds of thousands of SATA drives on SAS expanders, and that's just in the last few years with Isilon and ECS. Most every major storage vendor has. Just weird that you're hanging onto conflicting opinions from enthusiast forums.

 

[T_Minus]

Respectfuly I disagree with you on everything. I mean about the vendors doing that and about your green drives statement.

The WD Green issue is a known fact and caused a lot of problems of the time.
Big vendors are using sas expanders with SATA drives another fact.

I'm a bit perplexed what exactly you're disagreeing with? It's one thing to disagree with an opinion it's another to say you are essentially ignoring the facts?

"I reject your reality and substitute my own!"

 

[Rand__]

The question is whether the firmware of the drives in large arrays have been significantly adjusted or not.
If so then utilization of regular SATA drives might still be 'not safe' despite the massive utilization

As I said since there are very few to no 'new' threads about this I don't think that this issue is a big one any more.

 

[Evan]

Got a couple of extra petabytes of isilon delivered last week to add to our existing isilon and ECS already installed, so far it works fine and in a high performance reliable way. I never looked at those systems closely, did not ever pay attention to how the backend was setup.
On this I would say I have sample size I can make comment on (or rather not since it just works)

 

[Black Ninja]

Dell EMC mostly offers all flash storage, unless you go to the huge archiving storage options then you can get mechanical drives which should be NL-SAS drives. Even if you get sata drives( which I dont see any reason to go sata over sas in this), don't forget that dell uses it's own custom firmware from the drive, to the expander to the controller and even the MB. In this case I think it will be ok
to use sata or whatever they put inside if they made it as a whole machine.

But getting mix of vendors and drives behind sas expander I think is bad idea. It's called sas expander for a reason not sata expander. One vendor don't know what the other does, you know why hgst are most compatible with LSI controlers - case they made the drive firmware for quite some time.

Is there any other reason to even consider sata drive on sas expander, except to use cheaper drives ? Like picking consumer drives and put them on enterprise hardware ?

And what kind of spec is "green" drive ? That's advertising term not technical. What WD call "green" is not the same specs drive what hgst will call green drive or other vendor's green. I don't like this color scheme for dummies , that makes it even harder for knowledgeble person to understand what this drive do differently and what it specs are.

 

[Black Ninja]

Big vendors are using sas expanders with SATA drives another fact.

Is it possible to back up this claim with any real-world example ? Which vendors are doing that ? Supermicro ?

Even the surveillance storage server from DELL EMC models shows it uses NL-SAS drives.

 

[croakz]

Dell EMC mostly offers all flash storage, unless you go to the huge archiving storage options then you can get mechanical drives which should be NL-SAS drives. Even if you get sata drives( which I dont see any reason to go sata over sas in this), don't forget that dell uses it's own custom firmware from the drive, to the expander to the controller and even the MB. In this case I think it will be ok
to use sata or whatever they put inside if they made it as a whole machine.

But getting mix of vendors and drives behind sas expander I think is bad idea. It's called sas expander for a reason not sata expander. One vendor don't know what the other does, you know why hgst are most compatible with LSI controlers - case they made the drive firmware for quite some time.

Is there any other reason to even consider sata drive on sas expander, except to use cheaper drives ? Like picking consumer drives and put them on enterprise hardware ?

And what kind of spec is "green" drive ? That's advertising term not technical. What WD call "green" is not the same specs drive what hgst will call green drive or other vendor's green. I don't like this color scheme for dummies , that makes it even harder for knowledgeble person to understand what this drive do differently and what it specs are.

Not sure where you get your info, but it's wrong enough not to correct any more. SMH.