Backup and Restore Basics - Part 02

After review about Tape Drive Technologies, you should be able to:
+ Describe the features of AIT, DLT, SDLT, and LTO drives

AIT Drives and Media

AIT 50GB Drive Specifications

Advanced Intelligent Tape (AIT) drives offer an exceptional combination of data integrity, speed, price, reliability, and storage capacity. AIT drives use a selfcleaning head, eliminating the need for periodic cleaning.

DLT Drives

Digital Linear Tape (DLT) drives utilize a linear serpentine recording pattern. The drive writes along one set of tracks from the beginning of the tape until the end of the tape. After reaching end of the tape, the tape moves in the opposite direction and another set of tracks is used for writing data. DLT 35/70GB drives and DLT 40/80GB drives write data in angled pattern, allowing higher density per cartridge. This angled pattern is known as Symmetric Phase Recording. For every backup, a direct track access (DTA) directory is recorded at the beginning of the tape. The directory includes the location of each file on the tape, including track numbers.

SDLT Drives

SuperDLT (SDLT) technology increases tape capacity and transfer rate by an order of magnitude over DLT technology. In addition, each HP SDLT drive has a second head to provide backward read-compatibility for DLT tapes. SDLT technological advancements ensure reliable, durable, economical tape storage.
SDLT drives have either capacities of 110/220GB (SDLT 220) or SDLT 160/320 (SDLT 320). Both the SDLT 220 and SDLT 320 utilize similar optical and magnetic technologies.

LTO Technology

Linear Tape-Open (LTO) technology was conceived by and continues to be developed jointly by HP, IBM and Seagate. LTO technology is an "open format" technology, which means that users will have multiple sources of product and media.

The open nature of LTO technology also provides a means of enabling compatibility between different vendors' offerings as well competitive pricing. In contrast, the SDLT and AIT drives have single sources.
The three LTO founding companies set up three processes — specification, licensing, and compliance.

Refer to: http://www.lto.org/technology/generations.html

Generation 6
With capacity of 6.25 TB (assuming a 2.5:1 compression), LTO Ultrium generation 6 provides data transfer speeds of up to 400 MB/s (assuming a 2.5:1 compression) and continues support of partitioning to enable functions like LTFS making tape easy to manage, encryption - helping to secure data, and WORM to address compliance needs.
Generation 5
Delivering 3 TB (assuming a 2:1 compression), up to 280 MB/s (assuming a 2:1 compression), and adds a new partitioning feature and Linerar Tape File System specification to provide enhanced file control and data management. The LTO Ultrium format generation 5 specifications were made available to licensees in January 2010.
Generation 4
Delivering 1.6TB (2:1 compression) and up to 800 GB native per cartridge, Ultrium format Generation 4 provides data transfer rates of up to 240 MB/second (2:1 compression), the LTO Ultrium format generation specification was made available to licensees in late December 2006.
Generation 3
Featuring capacities of 800 GB (2:1 compression) and up to 400 GB native per cartridge, Ultrium format Generation 3 provides data transfer rates of up to 160 MB/second (2:1 compression) for the third generation of the 8-channel version. Generation 3 licenses became available on July 26, 2004 with products appearing in late 2004.
Generation 2
With a cartridge capacity of up to 400 GB (2:1 compression) and up to 200 GB native, Ultrium format Generation 2 provides data transfer rates of up to 80 MB/second (2:1 compression). Licenses for Generation 2 became available in April 2002 with products appearing in late 2002.
Generation 1
First licensed in 1998, with product appearing in 2000, Ultrium format Generation 1 provides cartridge capacities of up to 200 GB (2:1 compression) and up to 100 GB native with data transfer rates of up to 40 MB/ second (2:1 compression).

Ultrium Generation 1 Drives

Ultrium Generation 2 Drives

Ultrium/SDLT Comparison

Find Tape Drives and Enclosures:
http://www8.hp.com/us/en/products/tape-drives-enclosures/index.html#!view=column&page=1

After review MSL5000 and SSL2020 Tape Libraries, you should be able to:
+ Describe the features of the SSL2020TL AIT Library
+ Describe the features of the MSL5000 family of tape libraries
http://www8.hp.com/us/en/products/tape-automation/product-detail.html?oid=3936307#!tab=models

MB/s to GB/hr Conversion Formulas

Tape drive capacities and throughput figures are often represented in gigabytes. Primary storage throughput figures are typically represented in megabytes. In the world of enterprise storage, it is important to learn the formulas for converting the megabyte term usage to gigabyte terminology. The preceding graphic demonstrates how to calculate this equation.
Example
5MB/s x 3.6 = 18GB/hr
18GB/hr x 16.66 = 299.88MB/min
299.88MB/min ÷ 60 = 4.998MB/s

Performing a Needs Analysis
The best way to familiarize yourself with the network and its data is to perform a needs analysis. From the needs analysis, you will have all the information necessary to design an EBS.
The needs analysis consists of three steps:
1. Create a network topology map.
2. Identify the backup window.
3. Categorize the importance of data.

Selecting the Appropriate Device
After you have gathered the information from the needs analysis and grouped the data into jobs, you are ready to select a backup device. This process consists of four steps:
1. Calculate the compressed transfer rate.
    For compression ratios greater than 1:1:
    Compressed rate = (Base rate x compression ratio) – (compression ratio)2
    Example: HP LTO-4 Ultrium 1840 Tape Drives
    (864GB/hr x 2) – 2exp2 = 1724GB/hr = 478.6973MB/s
2. Adjust the compressed rate for feed speed and lights-out operations.
    You can reduce the compressed rate by 50% depend on feed speed
    Example: If full backups are more than one tape capacity, reduce the compressed rate by 3%.
    If performing incremental or differential backups, reduce the compressed rate by 14%.
3. Determine the number of drives needed to meet the backup window.
   The total data divided by the adjusted compressed rate equals the total hours of backup for one drive.
                  Hours of backup for one drive = (total data) / (adjusted compressed rate)
   The total hours for one drive divided by the backup window equals the number of drives needed.
                  Number of drives needed = (hours of backup for one drive) / (backup window)
   If performing full backups, the mechanical process of changing tapes could reduce the base backup rate by up to 7%.
   Incremental backups have slower backup rates than full backups because all the data on the system must be read to determine which files are new or have been modified since the last backup.
4. Determine the quantity of retained media.
   If the company estimates that 10% of its data files are changed or added to in some way each day, an incremental backup would have a value, on average, of 10%. If they use differential backups, the value for each set will be 10% x the number of days since the last full backup.

   Calculate the total retained percentage by calculating the value of the backup sets produced during the retention period.
Example
• If the company performs weekly full backups (F), no partial backups, and retains backup sets for three weeks before overwriting them, the total retained percentage would be:
            F x 3 = 100% x 3 = 300%
• If the company performs weekly full backups, incremental backups (I) on the other four days of the week, and retains for three weeks, the total retained percentage would be:
            (F + I + I + I + I) x 3 = (100 + 10 + 10 + 10 + 10) x 3 = 420%
• If the company performs weekly full backups, differential backups (D) on the other four days, and retains sets for three weeks, the total retained percentage would be:
           (F + D + D + D + D) x 3 = (100 + 10 + 20 + 30 + 40) x 3 = 600%
4. Calculate the storage capacity of each tape:
Tape capacity (SDLT) = 110GB x compression ratio
Tape capacity (DLT) = 40GB x compression
Tape capacity (AIT) = 50GB x compression ratio
Calculate the number of tapes required:
           # tapes required = (total data x retained percentage) / tape capacity