[SAC] Server quote/discussions

[Alex Mandel]

Alex Mandel wrote:
> 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

Quick follow up and good read
http://www.tomshardware.com/reviews/RAID-SCALING-CHARTS,1662.html

Makes me ponder only getting 6 drives to reduce the probability of failure.

Alex