Al Hopper wrote: > 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). > > I think the situation will change with the current expansion in RAM sizes. Five years ago with mainly 32 bit x86 systems, 4G of ram was a lot (even on most Sparc boxes). Today 32 and 64GB are becoming common. Desktop systems have seen similar growth.
ZFS also uses system RAM in a way it hasn't been used before. Memory that would have been unused or holding static pages is now churning rapidly, in a way similar memory testers like memtest86. Random patterns are cycling though RAM like never before, greatly increasing the chances for hitting a bad bit or addressing error. I've had RAM faults that have taken hours with memtest86 to hit the trigger bit pattern that would have gone unnoticed for years if I hadn't seen data corruption with ZFS. ZFS may turn out to be the ultimate RAM soak tester! -- Ian. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
