[YLUG] Server purchase

[Gavin Atkinson]

On Fri, 2006-05-19 at 12:01 +0100, Robert Hulme wrote:
> If you want cheap boxes then I would recommend a rack mount case from
> xcase (http://www.xcase.co.uk/acatalog/Rackmount_and_Server_Cases.html).
> In terms of CPU power if you go the opteron route you have to use ECC
> RAM which is a lot more expensive (but also more realiable!), but the
> X2 line of Athlon64's are effectively dual core versions of the same
> chip (so much more CPU power), are a lot cheaper (clock for clock),
> don't require expensive (where expensive in these terms is > £100)
> motherboards, andcan use normal RAM.

In my opinion, it is absolute madness to not use ECC memory in a server
that you need to rely on even slightly.

According to Wikipedia/DRAM, "A reasonable rule of thumb is to expect
one bit error, per month, per gigabyte of memory".  If that bit is in
some memory about to be written to the database filestore, you've got a
corrupt database.  If it's in the in-core copy of the filesystem free
block map, you may end up with random disk corruption.  If it's in some
other structure in memory, the server may panic.

ECC memory gives you a much higher chance of surviving random memory
errors, and also making diagnosing hardware faults in the future so much
easier.  For the difference in cost, it's just not worth not getting ECC
memory.

Gavin