Module 5: Block, File & Object Based Storage Systems (File Based Storage Systems)

Question 1

How do applications access data?

Answer 1

in the form of files

Question 2

What is metadata?

Answer 2

additional data that describes the raw data in the file (EX: picture file is a JPG/PNG)

Question 3

What is a file system?

Answer 3

logical representation of how an OS manages where and how data is stored

Question 4

How are files stored?

Answer 4

typically in folders - folders organized in hierarchical tree structure to be directly accessed or searched sequentially

Question 5

What is included in file metadata?

Answer 5

describes how an app can access the raw data in the correct format

Question 6

What is the relationship between hosts and file systems?

Answer 6

each server has its own file system - that file system is only accessible to that server

Question 7

What is file sharing?

Answer 7

allows access to different file systems across different hosts

Question 8

What is the relationship between servers and file sharing in general purpose file sharing?

Answer 8

benefits of file sharing degrade as more general purpose servers are added to share pool

Question 9

What are the major issues with network file sharing?

Answer 9

lack of scalability
file system incompatibilities across OSs
complex admin and data maintenance

Question 10

What are the two main OSs in file systems?

Answer 10

Windows and Linux

each based on different set of protocols - cross file sharing between OSs is a complicated process

Question 11

What is NAS (network-attached storage)?

Answer 11

purpose built file storage systems that take the place of general purpose servers for file sharing and storage

Question 12

What are the benefits of NAS over general purpose servers?

Answer 12

centralizes file share operations
uses specialized and optimized file IO
enables Linux UNIX and Windows users to share data more efficiently

Question 13

What is clustering in a NAS system?

Answer 13

enables multiple NAS controllers or nodes to function as a single entity - allow for workload distribution

Question 14

What are the two components of a NAS system?

Answer 14

NAS Controller
File Storage

Question 15

What is a NAS controller?

Answer 15

compute system that contains network, memory, and CPU resources for NAS

houses specialized file OS

responsible for managing RAID, creating LUNs, installing file systems and exporting file shares

Question 16

What is file data storage?

Answer 16

block based storage is used to store raw NAS data and metadata

Question 17

What is scale-up NAS?

Answer 17

provides the ability to independently grow capacity and performance

if you only scale compute or only scale storage that’s scaling up

Question 18

What happens when a NAS begins approaching it’s capacity limits?

Answer 18

performance of system starts degrading

Question 19

What is scale-out NAS?

Answer 19

ability to increase storage and compute simultaneously

Question 20

What are the benefits of scale out NAS?

Answer 20

pools multiple Nodes to work as single device

scales performance/capacity simultaneously

clients connected to any node can access any file system on the cluster

stripes data across nodes with mirror or parity protection

Question 21

How does scale out NAS networking work?

Answer 21

internal network provides intra cluster communication - each node connects to internal network

external network connection enables clients to access and share file data

Question 22

What are the features of the internal network for scale-out NAS?

Answer 22

offers high throughput and low latency

high speed networking like Infiniband or Gigabit Ethernet

Question 23

How do clients access the nodes in scale out NAS?

Answer 23

nodes must be connected to external Ethernet network

Question 24

What is CIFS?

Answer 24

CIFS = client internet file system - enable clients to make requests from file systems on remote computers over TCP/IP

Question 25

What is the difference between CIFS and SMB?

Answer 25

CIFS is non-proprietary version of SMB (server message block) which is made by Microsoft

Question 26

How does CIFS enable file sharing?

Answer 26

using special locks

Question 27

What are the features specific to CIFS?

Answer 27

uses file and record locking to prevent user overwriting

supports fault tolerance and automatically restore connections/files during interuptions

Question 28

What is the naming scheme for remote file systems?

Answer 28

\server\share or \servername.domain.suffix\share

Question 29

What is NFS?

Answer 29

network file system - common file protocol for UNIX systems

uses machine independent model to represent data

Question 30

What is used for inter-process communication between two computers running NFS?

Answer 30

Remote Procedure Call (RPC)

Question 31

What is HDFS?

Answer 31

Hadoop Distributed File System - supported by many of the major NAS vendors

Question 32

What is required to run HDFS?

Answer 32

requires programmatic access because the file system can’t be mounted

all HDFS communication is layered on top of TCP/IP protocol

Question 33

What type of architecture does HDFS run on?

Answer 33

primary and secondary

cluster consists of single Name Node that acts as management server

Question 34

What is an HDFS cluster made up of?

Answer 34

has in-memory maps of every file - file locations - and blocks within the files where Data Nodes reside

Question 35

What is the Name Node responsible for in HDFS?

Answer 35

manages file system namespace and controls access to the files by clients

Question 36

What are Data Nodes responsible for in HDFS?

Answer 36

serve read/write creations and perform block creation/deletion/replication

Question 37

What are the features of an HDFS file system?

Answer 37

spans multiple nodes and enables user data to be stored on files

traditional hierarchical file system

presents streaming interface to run apps through MapReduce framework

Question 38

What is FTP?

Answer 38

protocol that enables transfer over an IP network

uses TCP as the transport protocol

Question 39

What is the read/write process of a scale up NAS?

Answer 39

client packages IO into TCP/IP and forwards it to network

NAS receives request from network and converts IO request to correct physical storage which is a block level IO

operation than performed on physical storage

when NAS receives data from physical storage it packages it into correct file protocol

NAS packages into TCP/IP again and sends back over network

Question 40

How is a write operation performed in a scale out NAS?

Answer 40

client sends file to NAS

node to which client is connected to receives the file

file is striped across the nodes

Question 41

How is a read operation performed in a scale out NAS?

Answer 41

client requests file

node to which client is connected to receives the request

node retrieves and rebuilds the file and gives to client

Question 42

What is true about scale-out NAS architecture?

Answer 42

even though client is only connected to one node at a time every read or write operation from that node is striped across whole cluster

Question 43

How does the connected node rebuild a file that’s been striped across multiple nodes in a read request?

Answer 43

uses back-end Infiniband network

Question 44

What is a data lake?

Answer 44

hub for data ingestion and consumption systems

allows customers to bring analytics to their data and avoid high cost of multiple systems