On 04/16/98 15:48:18 you wrote:
>
>On Thu, 16 Apr 1998, Weeks, Thomas wrote:
>
>> RAM on the filer is being run to the very MAX of its specs
>> (maybe more)... I hear that they have a fairly high failure rate on RAM
>> that would otherwise work FINE in slower, less demanding systems (PC's).
>
>'scuse me??? Really? I find this somewhat hard to believe...
>
>60ns RAM is widely available, are you saying they're pushing the envelope
>on that?
>
>I very much doubt the memory architecture on a NetApp is anything more
>sophisticated than Sun's memory architecture (and I almost guarantee Sun's
>memory architecture blows away low-end NetApps)...and Sun seem able to use
>fairly standard parts without too much failure.
>
>Maybe I'm just missing the big picture...
Part of it is history. Back in the "old days", which is to say only 2-3 years
ago in computer time, there were lots of vendors you could get 60ns RAM from
that weren't quite up to snuff under heavy loads. And those vendors that did
often produced RAM that stood up to their tests, but not to Netapp's. As
the industry has progressed, I'm sure today's 60ns RAM chips are of higher
quality, so failures may be less common than they once were.
But yes, Netapp seriously pushes the performance of memory under high load,
even if that is now more easily within the tolerances of most memory chips.
Another thing to consider is that if you don't run your filers under very
high load, it's probably very easy for you to "get away" with lower-quality
memory. But don't be surprised if your filer starts getting memory errors
once you start running your CPU at 100%, or your cache age at 1, or you have
a disk failure and have to do reconstruction while in service, etc.
Bruce