Question

Rackspace Cloud Hosting

**Domain.com**
DynDNS
Private Whois
Full DynDNS Name servers and DNS
Remove www to domain.com

**Server Magento 1**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
APC
Memcache

**Server Magento 2**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
APC
Memcache

Server Magento 1 and Server Magento 2 (Load Balanced + will be in replication)

**DB Server 1**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
Memcache
MySQL 5

**DB Server 2**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
Memcache
MySQL 5

DB Magento 1 and DB Magento 2 (Load Balanced + will be in replication)

**CDN Server**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
APC
Memcache

CDN server will be in sync using C Names to MaxNDA, Cloud files or S3

Answer 1

I would suggest you:

**Server Magento 1**
1024 MB DDR (may be to low)
40 GB HD
Nginx
PHP-FPM
APC: only for opcode
cache: file because you don't have enough memory to use APC

**Server Magento 2**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
APC: only for opcode
cache: file because you don't have enough memory to use APC

Server Magento 1 and Server Magento 2 (Load Balanced + will be in replication)

**DB Server 1**
1024 MB DDR
40 GB HD

**DB Server 2** 
1024 MB DDR
40 GB HD

DB and DB2 (DB2 is just a copy of DB1 used for backup)
(some people use one db for writing and the other for reading)

**CDN Server**
1024 MB DDR
40 GB HD

other possibilities with distributed caching:

**Server Magento 1**
1024 MB DDR (may be to low)
40 GB HD
Nginx
PHP-FPM
APC: only for opcode
cache: fast backend memcache db2 and slow backend database

**Server Magento 2**
1024 MB DDR
40 GB HD
Nginx
PHP-FPM
APC: only for opcode
cache: fast backend memcache db2 and slow backend database

Server Magento 1 and Server Magento 2 (Load Balanced + will be in replication)

**DB Server 1**
1024 MB DDR
40 GB HD

**DB Server 2** 
1024 MB DDR
40 GB HD
memcache

**CDN Server**
1024 MB DDR
40 GB HD