## **Topic**: Backup 321 Rule and Storage Solutions

### **Speaker**: Galen Chen, 20240323

### **Lecture Content**

#### **Understanding the Backup 321 Rule**
- The 321 backup rule is a strategy for data backup that ensures data safety by keeping multiple copies of data on different media and locations. It involves having:
- At least 3 total copies of your data.
- 2 local copies on different devices or platforms.
- 1 copy off-site, such as in the cloud or on an external HDD/SSD or NAS.

#### **Components of a Backup Strategy**
- **Laptop SSD**: Using the onboard SSD for one of the local backups.
- **Cloud Storage**: Utilizing cloud services as an off-site backup location. Concerns include the risk of ransomware like WannaCry, account failure, and the reputation of the cloud provider.
- **External HDD/SSD and NAS**: For local backups, with NAS providing more sophisticated options like file versioning and snapshots.

#### **Considerations for Data Partitioning**
- **D Partition**: A separate partition on the same drive offers some organizational benefits but does not protect against SSD failure, power supply issues, or natural disasters.

#### **NAS (Network Attached Storage)**
- An advanced solution for local backups, offering features like RAID configurations for redundancy and improved data safety.

#### **Storage Size Explanation**
- Differentiates between the decimal and binary measurements of storage size, clarifying that 1TB can be considered as either 1000GB (decimal) or 1024GB (binary), and highlights the formula for converting between these measurements.

#### **RAID Configurations**
- **RAID 0 vs RAID 1**: Comparison between striping data across disks for performance (RAID 0) and mirroring data for redundancy (RAID 1).
- **RAID 5**: Introduces the concept of parity data to allow for data recovery in the event of a single disk failure.

#### **Choosing a NAS**
- Discussion on the Synology DSM system, considering file versioning, snapshot features, and the overall cost and benefits of owning a NAS for backup and storage solutions.

#### **Network and Cost Considerations**
- **Network Adapter Speed**: Explains the bandwidth of network adapters in relation to file transfer speeds.
- **Cost Analysis**: Breaks down the costs associated with purchasing a NAS setup and compares it to cloud storage pricing.

### **Take Home Messages**
- The Backup 321 rule is a comprehensive strategy to ensure data safety across different media and locations.
- Choosing the right storage solution involves considering factors such as redundancy, access speed, and cost.
- NAS systems offer robust backup options with features like RAID and file versioning, but their benefits need to be weighed against their initial and ongoing costs.

### **Q&A**
- **Question**: Is syncing cloud storage with an onboard SSD a good strategy?
- **Answer**: It can be part of a backup strategy but beware of potential risks like ransomware and account failures.

- **Question**: What happens if the D partition fails?
- **Answer**: Since it's on the same physical drive as the main partition, a hardware failure would affect it too, emphasizing the importance of external backups.

- **Question**: Should I get a NAS?
- **Answer**: It depends on your storage needs, the value you place on data redundancy and recovery options, and whether you're willing to invest in the initial setup and ongoing costs.

#### **Comparing RAID Levels: 0, 1, 10, 5, 6**

| Feature | RAID 0 | RAID 1 | RAID 10 | RAID 5 | RAID 6 |
|-----------------------|----------------------------------|----------------------------------|------------------------------------------|------------------------------------------|---------------------------------------------|
| **Description** | Striping without redundancy | Mirroring without striping | Combines striping and mirroring | Striping with parity | Striping with double parity |
| **Minimum Disks** | 2 | 2 | 4 | 3 | 4 |
| **Redundancy** | None | Yes, through mirroring | Yes, through mirroring | Yes, through parity | Yes, through double parity |
| **Fault Tolerance** | None | Can tolerate 1 disk failure | Can tolerate at least 1 disk failure | Can tolerate 1 disk failure | Can tolerate 2 disk failures |
| **Storage Efficiency**| High (100% of disk space used) | Low (50% of disk space used) | Medium (50% of disk space used) | High (N-1)/N of disk space used | Medium (N-2)/N of disk space used |
| **Performance** | High read and write speeds | High read, lower write speeds | High read and write speeds | High read speeds, lower write speeds | Lower read and write speeds compared to RAID 5 |
| **Best Used For** | Non-critical data where speed is important | Critical data requiring redundancy | Critical applications requiring high performance and redundancy | Systems where both performance and economy are desired | Environments requiring a high degree of fault tolerance |

### Original notes

Backup 321 rule
- Laptop ssd
- Cloud, mirror
- External HDD/SSD; NAS (Network Attached Storage)

Cloud + Onboard SSD? Sync?
- Wannacry? (without file versioning)
- Account failure
- Company reputation?

D partition?
- SSD failure
- Power supply
- natural disaster

NAS

Storage size:

1TB = 1000GB; 1GB = 1000MB; 1MB = 1000KB; 1KB = 1000B
1TB = 1024GB; 1GB = 1024MB; 1MB = 1024KB

TB* = (1000/1024)^4 TB
1024 = 2^10

RAID
RAID, Redundant Array of Independent Disks
RAID0 vs RAID1
RAID 5: parity data

Synology DSM

file versioning and snapshot