Data center selection guide: Tier classification, power redundancy, cooling systems, physical security, network connectivity and SLA guarantees. TIER 3 data center in Turkey.
Data center selection directly determines the reliability and performance of your server infrastructure. A wrong data center choice can lead to unexpected outages, data loss, and business continuity issues. This guide explains all the critical factors to consider when choosing a data center.
The Uptime Institute classifies data centers into four Tier levels. This classification determines the reliability and uptime guarantee of the data center.
Tier 1 Features:
- Annual uptime: 99.671%
- Annual downtime: 28.8 hours
- Power: Single path
- Cooling: Single path
- Maintenance: Requires downtime
- Use: Small businesses, test environments
Tier 2 Features:
- Annual uptime: 99.741%
- Annual downtime: 22 hours
- Power: N+1 redundant
- Cooling: N+1 redundant
- Maintenance: Partial downtime required
- Use: Medium-sized businesses
Tier 3 Features:
- Annual uptime: 99.982%
- Annual downtime: 1.6 hours
- Power: N+1 or 2N redundant
- Cooling: N+1 redundant
- Maintenance: Can be done without downtime
- Use: Enterprise applications, e-commerce
Tier 4 Features:
- Annual uptime: 99.995%
- Annual downtime: 26.3 minutes
- Power: 2N+1 fully redundant
- Cooling: 2N fully redundant
- Maintenance: Completely uninterrupted
- Use: Critical infrastructure, finance, healthcare
| Feature | Tier 1 | Tier 2 | Tier 3 | Tier 4 |
|---|---|---|---|---|
| Annual Uptime | 99.671% | 99.741% | 99.982% | 99.995% |
| Annual Downtime | 28.8 hrs | 22 hrs | 1.6 hrs | 26 min |
| Power Paths | 1 | 1+backup | 2 | 2+backup |
| Cooling | Single | N+1 | N+1 | 2N |
| Maintenance | Disruptive | Partial | Non-disruptive | Non-disruptive |
Minimum Tier 3 is recommended for enterprise use. Tier 3 means only ~1.6 hours of downtime per year and is sufficient for most businesses.
N → Single power source (minimum)
N+1 → One backup power source
2N → Double copy of everything
2N+1 → Double copy + extra backup
UPS ensures servers continue to operate during grid outages.
Things to Check:
- Is UPS capacity sufficient?
- Battery age and maintenance status
- Automatic transfer time
- Is bypass mode available?
Generator Features:
- Fuel type: Diesel (preferred)
- Startup time: < 30 seconds
- Fuel capacity: How many hours?
- Automatic fuel replenishment agreement?
- Test frequency: Monthly testing?
Servers generate a lot of heat. Insufficient cooling leads to hardware failures and shortened lifespan.
PUE = Total Facility Power / IT Equipment Power
PUE Assessment:
1.0: Excellent (theoretical minimum)
1.2: Very good
1.5: Good
2.0: Average
> 2.0: Inefficient
Cold Aisle: Front of servers (air intake)
Hot Aisle: Back of servers (air exhaust)
Benefits:
- Prevents mixing of cold and hot air
- Increases cooling efficiency
- Saves energy
Security Layers:
1. Perimeter security (fence, camera)
2. Building entrance (security personnel)
3. Data center entrance (card reader)
4. Rack room entrance (biometric)
5. Individual rack lock
Mantrap Operation:
1. Person enters outer door
2. Outer door closes
3. Authentication is performed
4. If approved, inner door opens
Advantage: Prevents unauthorized entry
Single Upstream (Bad):
Data Center → ISP A → Internet
Risk: If ISP A fails, all connectivity is lost
Multiple Upstream (Good):
Data Center → ISP A → Internet
→ ISP B → Internet
→ ISP C → Internet
Automatic load balancing and failover with BGP
IX points are where different networks connect directly to each other. IX connectivity provides:
SLA Checklist:
✓ What is the uptime guarantee? (99.9%, 99.99%?)
✓ How is downtime measured?
✓ Is planned maintenance included in SLA?
✓ What is the compensation rate?
✓ Is compensation automatic or does it require a request?
✓ What is the maximum compensation amount?
✓ What is the notification period?
REXE Technology serves from a TIER 3 certified data center in Istanbul.
REXE Data Center Features:
Tier Certification:
- TIER 3 certified
- 99.982% uptime SLA
- ~1.6 hours maximum downtime per year
Power Infrastructure:
- N+1 UPS system
- Diesel generator (72+ hours of fuel)
- Automatic transfer switch
Cooling:
- N+1 CRAC units
- Hot/cold aisle separation
- PUE < 1.5
Physical Security:
- 24/7 security personnel
- Biometric access control
- CCTV system
- Mantrap entry
Network Connectivity:
- Multiple upstream via Path.net
- Turkey IX connectivity
- BGP routing
- Tbps-capacity DDoS protection
Don't just look at price when choosing a data center. Tier certification, power redundancy, and network connectivity quality are much more important in the long run. REXE's TIER 3 infrastructure provides enterprise-level reliability.
Tier 3 offers ~1.6 hours of downtime guarantee per year, while Tier 4 offers only ~26 minutes. Tier 4 provides full fault tolerance — the system continues to operate when any component fails. However, Tier 4 costs much more than Tier 3. Tier 3 is sufficient for most businesses.
N represents the minimum number of power sources required. N+1 means there is one more backup power source. For example, if 3 UPS units are needed (N=3), an N+1 configuration has 4 UPS units. When one unit fails, the system continues to operate.
Network connectivity determines your server's internet access. A data center connected to a single upstream provider becomes completely inaccessible when that provider has an outage. Multiple upstream and BGP routing provide high availability. IX connectivity also provides lower latency for local traffic.
Yes, the Istanbul data center used by REXE is TIER 3 certified and compliant with international standards. ISO 27001 information security management system certification is also available. Data centers in Turkey are operated in compliance with KVKK and international data protection standards.
Data center SLA covers the uptime guarantee of the physical infrastructure (power, cooling, network connectivity). Server SLA guarantees the accessibility of the server itself. REXE's server SLA offers end-to-end 99.99% uptime guarantee including data center infrastructure and network connectivity.
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