[SAC] Server quote/discussions

[Alex Mandel]

Martin Spott wrote:
> On Mon, Feb 01, 2010 at 11:26:56PM -0500, Daniel Morissette wrote:
> 
>> What I meant was that instead of two 7.5k$ machines (15k$) we could  
>> possibly get more power, storage and redundancy out of a cluster of four  
>> 3k$ machines (12k$), by going with (cheaper) SATA disks and sticking to  
>> 16-32GB RAM per box (using 2-4GB DIMMs) instead of going with the more  
>> expensive 8GB or 16GB DIMMs.
> 
> I agree partially since nowadays you're already getting pretty nice
> boxes for small money, for example at Sun Microsystems (or Dell,
> whereas Sun would certainly be my personal favourite).
> 
> But please don't use cheap disks. Low latency at the disk subsystem is
> a top priority for setups with pretty much 'random' load like here,
> even more when you're going for virtualization, and making a bad
> decision here is going to hurt you for years - without having much of a
> handle to fix it.
> 
> Therefore I'd say that 10k or 15k SAS disks and no RAID6 !! (have you
> ever seen a fast as well as reasonably priced RAID6 controller ?) is
> almost a must.
> 
> Cheers,
> 	Martin.

We are looking at either 10k or 15k SAS, no less.

Do you have any recommendations on a fast RAID6 controller.
RAID 5 does seem like a better choice since speed has been one of our
biggest issue, however the risk to the data concerns me.
This issue of disk i/o is actually why SATA is out of the running.
(Anyone know if the current systems have RAID x?)
On the current system quotes - we will opt for the Perc H700 to get the
6 GB/s throughput - this card can do most RAID configurations, still
looking for benchmarks. So it looks like we can make that decision after
the purchase.

I will have to check if the hosting cost for 3 or 4 machines is going to
be more than 2 machines. Power and people time can easily surpass the
difference in the cost of the machines in a couple of months. I would
also note that managing that many more physical machines is something to
be concerned about.

That said 3 servers might be a good option with the 3rd machine being
spec'd either as a storage device with slower drives for the less
critical apps/backup or handling things like LDAP with the other 2
servers doing the grunt work.

Thanks,
Alex