Data Storage Solutions

1. Data Storage Solutions Module 1.2

2. Data Storage Solutions Upon completion of this module, you will be able to: • List the common storage media and solutions. • Describe the three common storage environments.

3. Lesson: Storage Solution Alternatives Upon completion of this lesson, you will be able to: • Describe the different media and solutions available to address data storage needs of a business. • Describe the role of each solution in the overall data storage needs. • Describe the advantages of disk arrays.

4. Common Data Storage Media • As the need for storing large amount of data grows, each of these can be combined and housed in central units. • A collection of tape drives and tapes – Tape library • A collection of optical disks and drives – Jukeboxes • A collection hard disks – Disk Arrays • Each solution addresses specific needs for data storage and management. • Tape Library – Backup/Restore; Archival of data • Jukeboxes – Typically to store non-changing content over long periods of time • Disk Arrays – To store data that has to be immediately accessible and on-line

5. Tape Storage Systems • Tape based storage is relatively inexpensive, compared to disk arrays. • They served as primary storage solutions in the early days. • Tape drives use Read/Write heads to record bits of data onto magnetic material on the tape surface. • Far from being abandoned, this technology continues to evolve, providing higher storage capacity, greater reliability, and improved performance.

6. Storing Data on Tape • Data is recorded sequentially from the beginning to end, one byte after another. • Because data is stored linearly along the length of the tape, random access to specific bits of data is slow and time consuming. This severely limits tape as a medium for real-time, rapid access to data. • Tapes cannot be shared among multiple users or applications.

7. Optical Data Storage • Popular in small, single-user computing environments. • Frequently used by individuals to store and share data, or as backup solution. • Also used as distribution medium for applications, or as a means of transferring small amounts of data from one self-contained system to another.

8. Disk Based Storage From a historical perspective, we will explore the following disk based storage solutions: • DASD: Direct Access Storage Device • JBOD: Just a Bunch Of Disks • Disk Arrays • “Intelligent” Disk Arrays

9. Disk Mainframe Types of Disk Systems: DASD • Introduced by IBM in 1956. • The ‘oldest’ of the techniques for accessing disks from a host computer. • Disks are accessed directly by a single host, historically a mainframe system.

10. Host Disk Disk Disk Disk Disk Types of Disk Systems: JBOD • Multiple physical disks in an external cabinet. • Array connects to a single server only. • Provides higher storage capacity with increased number of drives. • Data not protected. Array

11. Types of Disk Systems: Disk Arrays • Array controllers for optimized I/O operations and RAID calculations. • Higher speed interconnects between drives, than JBODs. • Multiple host I/O channels. • Can be partitioned to allow each host to access its own set of drives. Host B Host C Host A Disk ArrayController Disk 1 Disk 2 Disk 3 Disk 4 Disk 5 Host A Host B Host C

12. Host Disk ArrayController Disk 1 Disk 2 Disk 3 Disk 4 Disk 5 Types of Disk Systems: “Intelligent” Disk Arrays • Highly optimized for I/O processing. • Cache for improving I/O performance. • Operating environments provide: • Intelligence for managing Cache, • Array resource allocation, • Host access to Array resources, • Connectivity for heterogeneous Hosts

13. Lesson: Summary Topics covered in this lesson included: • Tape • Optical • Disks • DASD • JBOD • Disk Arrays • Intelligent Disk Arrays

14. Lesson: Storage Environment Upon completion of this lesson, you will be able to: • Describe Direct Attached Storage (DAS) features. • Describe Storage Area Network (SAN) features. • Describe Network Attached Storage (NAS) features.

15. DAS Server AApplication A Client 1 Disks for Server A Network Disks for Server B Client 2 Server BApplication B Disks for Server C Client 3 Server CApplication C

16. NAS NAS Device AFile System A Disks for File System A Internal/External connectivityto disks or arrays NAS Device BFile System B Disks for File System B

17. SAN Server AApplication A Client 1 Disks for Server A SAN Disks for Server B Client 2 Server BApplication B Disks for Server C Client 3 Server CApplication C

18. Direct Attached Storage (DAS) • Characteristics:-Storage devices attached directly to servers (only point of access)

19. DAS, cont. • Components-Most use SCSI-Most use a redundant array of independent disks (RAID) to protect data against single-disk failure-Server is the performance bottleneck

20. DAS, cont. • Strengths & Limitations:-They are relatively inexpensive, familiar to most IT departments, and are widely usable.-However, single-server access is limiting, and DAS networks have distance limitations

21. Network Attached Storage (NAS) • Characteristics:-Essentially specialized servers dedicated to storage provision-Unlike DAS, NAS allows any user to directly access resources-Typically use platform-independent file systems

22. NAS, cont. • Components:-Storage appliance contains a “thin” server-Server uses its own host-independent filesystem-Connects directly to the LAN

23. NAS, cont. • Strengths & Limitations:-NAS enables faster access to applications, multiple servers can access the same device, and a NAS is more reliable than a DAS-A NAS environment is limited by LAN bandwidth, and can still bottleneck at the NAS server itself

24. Storage Area Networks (SANs)

25. SANs, cont. • Components:-Fibre Channel is the most common interconnect technology.-Can use a variety of media, including fiber optic cables, coaxial cables, or twisted pair wiring.-Other components include HBAs, transceivers, hubs, and switches.

26. SANs, cont. • Strengths & Limitations:-Provide highly scalable performance, allow hosts to implement storage file systems (allowing them to use file systems best suiting their applications).-SANs are also much more expensive than other storage networking solutions, and do not allow heterogenous operating systems to access the same storage resources.

27. Organizations & Standards • Storage Networking Industry Association (SNIA) • Fibre Channel Industry Association (FCIA) • International Committee for Information Technology Standards (iNCITS) • Supported Solutions Forum (SSF) • SANmark Qualified Program • Open Standards Fabric Initiative (OSFI) • Shared Storage Model

28. Lesson: Summary Topics covered in this lesson included: • Direct Attached Storage (DAS) features. • Network Attached Storage (NAS) features. • Storage Area Network (SAN) features.

29. Module Summary Key points covered in this module: • The three types of data storage media. • The three storage interconnect models.

30. Check Your Knowledge  • What are the three most common storage media? • What are the three types of disk-based solutions? • What are the advantages of a disk-based storage solution? • What are the three storage interconnect models? • Why is a SAN solution the best alternative for large storage environments?