SystemStorage Flashcards
What are the two main categories of physical storage based on power dependency?
Volatile and Non-volatile storage
What is the key characteristic of volatile storage?
It loses its contents when power is switched off
What is the key characteristic of non-volatile storage?
It retains its contents even when power is switched off
What is the primary example of volatile storage?
Random Access Memory (RAM)
What are the 7 factors to consider when selecting storage solutions?
Access Speed Capacity Cost Reliability Power Consumption Physical Size Scalability
What is the access time of L1 Cache?
Less than 1 nanosecond
What are the three main levels of storage hierarchy groups?
Primary storage (volatile) Secondary storage (online) Tertiary storage (offline)
What are the 3 main storage interfaces?
SATA SAS NVMe
What is the maximum data transfer speed of SATA 3.0?
6 Gbps
What is the maximum data transfer speed of SAS-3?
12 Gbps
What are the key components of an HDD?
Platters Read/Write Heads Actuator Arm Spindle
What is a sector in HDD?
The smallest unit of data that can be read/written (typically 512 bytes)
What are the two components of HDD access time?
Seek Time and Rotational Latency
What are the main components of an SSD?
NAND Flash Memory Controller Cache Host Interface
What is wear leveling in SSDs?
Technique to assign “cold data” to frequently erased pages and “hot data” to less erased pages
What is RAID?
Redundant Array of Independent Disks - technology combining multiple disk drives into a logical unit
What is the key feature of RAID 0?
Data striping across drives with no redundancy
What is the key feature of RAID 1?
Data mirroring across two or more drives
What is the key feature of RAID 5?
Striping with distributed parity across all drives
What’s the difference between SAN and NAS?
SAN provides block-level access while NAS provides file-level access
What is the typical access time range for RAM?
50-100 nanoseconds
What is the typical access time range for SSDs?
20-100 microseconds
What is the typical access time range for HDDs?
5-10 milliseconds
What is the main advantage of NVMe over SATA?
Lower latency and higher throughput due to direct CPU connection
What is the purpose of CPU cache?
To store frequently accessed data and instructions
What is the capacity utilization of RAID 1?
50% of total drive capacity
What is the purpose of garbage collection in SSDs?
Reclaims space from deleted data
How many erase cycles can a typical NAND flash cell endure?
100000 to 1000000 erases
What is the function of the HDD controller?
Interface between computer system and hardware accepts high-level commands
What is data striping?
Technique of splitting data across multiple drives to improve performance
What components make up the storage hierarchy from fastest to slowest?
CPU Registers -> CPU Cache -> RAM -> SSD -> HDD -> Network Storage -> Tape Archives
What is the primary advantage of RAID 6 over RAID 5?
Better reliability due to double parity blocks
What is hot swapping in RAID systems?
Ability to replace disk while system is running
What is data scrubbing in RAID?
Continually scanning for latent failures
What is the primary use case for RAID 10?
High-performance databases requiring both redundancy and speed
