Hi Bryan,

  *   San Storages shall Mirror Each Other for full storage redundancy.

I’d highly recommend placing the mirror SAN in a separate rack.


  *   Additional harddrives to be added to the San Storages as when needed.
Do you plan for disk shelves in the same rack?


  *   Server Capacity shall be configured in the CloudStack Platform to not 
provision more than 30% (within its cluster) to allow for Auto VM Restart in a 
new server, should any server fail.

I’m not sure I get this.
Based on a principle of N+1 redundancy if you have 2 hosts you can use each up 
to 50% capacity, 3 hosts =  66% capacity, 4 hosts = 75% capacity, etc…etc…  I 
don’t see any scenario where using only 33% capacity makes any sense.

Where do you plan to run your management servers and DB from? This same rack or 
outside it?

>We haven’t decided if we are going to be standardising our servers within the 
>rack to be (2x26pCPU) or (2*64pCPU).
I’d recommend something in between. Also depends a lot on how much RAM you’ll 
add those servers, you want to make sure you have a balanced use of CPU/RAM 
(keep in mind that you can run ACS with 3:1 CPU overcommitment, but RAM you 
want to keep 1:1 typically)

>Our guys have recommended a 2x50TB Hybrid SSD/HDD San Storage at 150k IOPS for 
>the entire rack. But we would like second opinions as we aren’t sure the 
>specifications are insufficient (Afraid that San Storage would be the 
>bottleneck one day). Ideally would be some sort of san storage spec which we 
>can >grow the IO over time as the number of servers in the rack increase (We 
>are starting with 2, plan to increase to max 14 over time).

3,000 IOPS per TB sounds quite low nowadays. But that really depends on your 
end-users usage patterns. But as a finger in the air I’d aim for a peak of 10k 
IOPS per TB.

Also, if you leave 1KW for switching (LAN and SAN) plus 2kw for the storage 
arrays, that leaves you with 3kw for your hosts, which means 8-10 hosts tops, 
will be hard to run 14. (but hard to say without knowing the switches and 
storage specs)

I’d also highly recommend using 25G networking on your hosts.

Cheers
Alex


From: Bryan Tiang <bryantian...@hotmail.com>
Sent: 25 November 2022 18:31
To: users@cloudstack.apache.org
Subject: Advice on Hardware Rack Design for Cloudstack

Hi Cloudstack Community,

Thanks for the help on the previous question regarding how to deploy instances 
on 2 different physical servers within a cluster.

I would like some advice from the community regarding our rack design, its our 
first time setting up a Private Cloud.

We plan to start off our cloud stack journey with a single rack (42u). We have 
come up with a visual to help understand bit better.



This is what we were thinking:

  *   All Infrastructures are Fully Redundant (Eg. Network, Server, Storage etc)
  *   Racks connected to two different PDU Power Sources ( Max 6KW Each)
  *   Each Server is connected to the SAN Storages within the Rack (will not 
cross out of the Rack)
  *   San Storages shall Mirror Each Other for full storage redundancy.
  *   Additional harddrives to be added to the San Storages as when needed.
  *   Server Capacity shall be configured in the CloudStack Platform to not 
provision more than 30% (within its cluster) to allow for Auto VM Restart in a 
new server, should any server fail.
  *   Servers will not have any Local Drives. All Storages are in the San 
Storage only.
  *   Minimum setup will include minimum 2 Servers.
Additional servers (with same CPU Models) to be added as requirements grow.


We haven’t decided if we are going to be standardising our servers within the 
rack to be (2x26pCPU) or (2*64pCPU).

Here’s where we need some advice. In both scenarios of the server spec, we 
aren’t sure what is the recommended (or safe) San Storage spec to go for. We 
plan to deploy various services in the VMs, but the most intensive would be 
MSSQL Databases which are very IO Intensive.

Our guys have recommended a 2x50TB Hybrid SSD/HDD San Storage at 150k IOPS for 
the entire rack. But we would like second opinions as we aren’t sure the 
specifications are insufficient (Afraid that San Storage would be the 
bottleneck one day). Ideally would be some sort of san storage spec which we 
can grow the IO over time as the number of servers in the rack increase (We are 
starting with 2, plan to increase to max 14 over time).

Any advice on this area? Even comments on our rack design would be great! We 
really want to start this on the right footing.

Regards,
Bryan






 

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