Is ECC ram and ZFS necessary?

[tangoseal]

I have been reading the general web and the consensus seems to be that ECC is 100% preferrable to 50% of the people and non ECC is 100% preferrable to the other 50%. So basically no one seems to have a definite answer.

Is there really any point to having ECC on a ZFS NAS (for home use) or any use for that matter? I mean how long does data sit in ram to have a bit switch on something anyways?

I am faced with my new build coming up and am looking at getting 32GB of Registered ECC (yeah the supermicro board I have chosen for socket 2011) will support it.

I just want to make sure. Even if it is not required I may still get it however it is good to atleast know for sure. Thanks.

 

[TCM]

Do you really think the 50%/50% crowds can suddenly decide based on yet another thread with the same question?

Just get ECC and be done with it. Peace of mind and all that stuff..

 

[drescherjm]

My opinion is if you are running a bank or other business that 1 bit being wrong in your TBs or PBs of data would be catastrophic then get ECC if this is a media center application don't bother.

BTW, I am now back from vacation so I will soon look at that other thread about ECC and ZFS when I get a chance..

 

[olavgg]

The price difference between ECC and no ECC memory is negligible. And ECC is safer!
Would you drive a car without airbags? Most likely you will never use it, but it might be very handy one unlucky day.

 

[tangoseal]

Yeah i get yall. So anyways registered ecc is cheaper than unbuffered. Cant answer as to why.

 

[Concentric]

One of the main advantages of ZFS is that it is able to detect and repair corruption in the stored data. If you use non-ECC RAM then you're in effect saying that you don't care about that feature, because the system cannot effectively detect and correct errors if the memory it's running on is also subject to random corruption.

Ask yourself why you are using ZFS - what features do you care about?

If you care about the integrity of your data (and in my opinion you should) then spend a little more and get the real deal - ECC memory. If you don't really care and just want the cheapest possible hardware then feel free to use non-ECC. ZFS doesn't require it.


EDIT: On the Registered/Buffered question - it's important to make sure you get what's compatible with your system - Registered/Buffered will not work with a memory controller designed for Unbuffered/Unregistered, and vice versa. http://en.wikipedia.org/wiki/Buffered_memory

 

[drescherjm]

Yeah i get yall. So anyways registered ecc is cheaper than unbuffered. Cant answer as to why.

Registered can use 4 times the # of chips than unbuffered. Lower density chips usually are more popular so they usually trade cheaper than the highest density chips for the same amount of ram.

 

[drescherjm]

because the system cannot effectively detect and correct errors if the memory it's running on is also subject to random corruption.

This goes on the assumption that a single bit flips on ram happens regularly and multiple bit flips do not happen. In my 15+ years of experience with server grade hardware that record every single ECC correction in the system event log accessible from the BIOS or OS utility that can read the log and desktop grade hardware at work I find this idea ridiculous.

 

[tangoseal]

Registered can use 4 times the # of chips than unbuffered. Lower density chips usually are more popular so they usually trade cheaper than the highest density chips for the same amount of ram.

So basically regustered are cheaper due to more smaller capacity chips crammed on to a pcb?

 

[drescherjm]

So basically regustered are cheaper due to more smaller capacity chips crammed on to a pcb?

Yes registered can be cheaper (its not always however) for this reason.