On Sat, Nov 15, 2008 at 9:26 AM, Richard Elling <[EMAIL PROTECTED]> wrote:
> dick hoogendijk wrote:
>> On Sat, 15 Nov 2008 18:49:17 +1300
>> Ian Collins <[EMAIL PROTECTED]> wrote:
>>
>>
>>> [EMAIL PROTECTED] wrote:
>>>
>>>> > WD Caviar Black drive [...] Intel E7200 2.53GHz 3MB L2
>>>> > The P45 based boards are a no-brainer
>>>>
>>>> 16G of DDR2-1066 with P45 or
>>>> 8G of ECC DDR2-800 with 3210 based boards
>>>>
>>>> That is the question.
>>>>
>>>>
>>> I guess the answer is how valuable is your data?
>>>
>>
>> I disagree. The answer is: go for the 16G and make backups. The 16G
>> system will work far more "easy" and I may be lucky but in the past
>> years I did not have ZFS issues with my non-ECC ram ;-)
>>
>
> You are lucky. I recommend ECC RAM for any data that you care
> about. Remember, if there is a main memory corruption, that may
> impact the data that ZFS writes which will negate any on-disk
> redundancy. And yes, this does occur -- check the archives for the
> tales of woe.
I agree with your recommendation Richard. OTOH I've built/used a
bunch of systems over several years that were mostly non ECC equipped
and only lost one DIMM along the way. So I guess I've been lucky also
- but IMHO the failure rate for RAM these days is pretty small[1].
I've also been around hundreds of SPARC boxes and, again, very, few
RAM failures (one is all that I can remember).
Risk management is exactly that. You have to determine where the risk
is and how important it is and how likely it is to bite. And then
allocate costs from your budget to minimize that risk. Remember that
you won't totally eliminate all risk - but you can minimize it. At
the time when there was a big cost delta between ECC and non ECC RAM
parts, I always went with the most (non ECC) RAM that the budget would
support. That was my personal risk assessment and priority. I think
it was a good decision and it did'nt cause me any grief.
[1] I do recommend that you test the heck out of new RAM parts and
ensure that they get some airflow - especially if they are getting a
supply of hot air from any nearby CPU coolers. Even the simple
"finger test" will tell you if you need a fan for your RAM DIMMs.
--
Al Hopper Logical Approach Inc,Plano,TX [EMAIL PROTECTED]
Voice: 972.379.2133 Timezone: US CDT
OpenSolaris Governing Board (OGB) Member - Apr 2005 to Mar 2007
http://www.opensolaris.org/os/community/ogb/ogb_2005-2007/
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