储存产品暨产业基本概要-XXXX

With RAID
I/O 1 (Disk 1) I/O 2 (Disk 2)
Time Saved
Software setup Access Time Data Transfer Software Completion
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Total request execution time
What is storage
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Infortrend Technology, Inc.
What is Storage?
• Devices which provide capacity for host
• Each Sector is 512 Bytes • Drive Capacity = 512 Bytes x Sectors x Cylinders x Heads
• Logical Block Address (LBA)
- Total block counts provided by drives - Actual useful capacity - Most of the operating systems support LBA
Disk 1
P(1,2) 4 5
P(7,8) 10 11
Disk 2
1 P(3,4)
6 7 P(9,10) 12
Disk 3
2 3 P(5,6) 8 9 P(11,12)
Striping with interspersed parity
P(2N-1, 2N) 2N-1
2N
N Blocks
Host LUN 1 2 3 4 5 6 7 8 9 10 11
14
RAID Levels
• NRAID • RAID 0 • RAID 1 • RAID 3 • RAID 5 • RAID 6
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15
RAID Basics – JBOD
Disk 1 Disk 2 Disk 3
Host LUN Disk 1 Disk 2 Disk 3
12
RAID Benefits: Storage Capacity
Without RAID
1
Drive Capacity
=
Single hard drive
capacity
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With RAID
…
N
…
N drives
Single
Drive = N x hard drive
Read / Write Heads
Arm
Platter
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Side View (Platters, Spindle and Arm)
Spindle Motor
Drive Capacity Calculations
• Cylinder, Head, Sector (C/H/S)
- Virtual Cylinder/Head/Sector counts provided by drives - May not 100% close to the actual capacity - Certain operating systems still use C/H/S
to wait for medium. 3. Write cached data to medium in
optimised order. (involved latency times)
Medium
Read
Host
Medium
Data
Cache Pool
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RAID Fundamental
Date: 30 June 2020
Infortrend Internal & Confidential
Infortrend Technology, Inc.
Agenda
• Hard Drive Basics • What Is Storage • RAID Basics • RAID Subsystem Basics • Infortrend Storage
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2
Hard Drive Basics
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Infortrend Internal & Confidential
Infortrend Technology, Inc.
Hard Drive Basics
Disk 3
N+N’+1 N+N’+2 N+N’+3 N+N’+4 N+N’+5 N+N’+6
N
Disk 1 has N
Blocks
N+N’
N+N’+N’’
Disk 2 has Disk 3 has
N’
N’’
Blocks
Blocks
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SwitchHBBiblioteka ; Host Bus Adapter
Read data or Write data from Host to RAID system
External RAID System (Storage)
9 Infortrend Internal & Confidential
RAID Basics
Disk 2 2 5 8 11 14 17
Striping
3N-1
Disk 3 3 6 9 12 15 18
3N
N Blocks
18 Infortrend Internal & Confidential
Host LUN 1 2 3 4 5 6 7 8 9 10 11
3N
RAID Basics – RAID 1 (Disk Mirroring)
• Cache
• Write-back cache can provide faster performance • Write-through cache ensures no cached data lost when power fails
• MTBF and Duty Cycle
• MTBF comparison should consider Duty Cycle • Higher Duty Cycle drives is more reliable when using in RAID
Capacity
capacity
(In example of RAID 0)
13
RAID Benefits: Performance
Performance @ N x Single Drive Performance
Without RAID
I/O 1
(In example of RAID 0)
I/O 2
Disk 4 Disk 5 Disk 6
Disk 4 Disk 5 Disk 6
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16
RAID Basics – NRAID (Disk Spanning)
Disk 1
1 2 3 4 5 6
Disk 2
N+1 N+2 N+3 N+4 N+5 N+6
2. Write completed when data has written on medium. (Wait for medium, latency time involved)
Write
Write-
Host Back
Data
Cache Pool
1. Host writes data into cache. 2. Write completed. Host does not have
17
Disk1 N
Blocks
Disk2 N’
Blocks
Disk3 N’’
Blocks
Host LUN 1 2 3
N N+1 N+2 N+3
N+N’ N+N’+1
N+N’+N’’
RAID Basics – RAID 0 (Disk Striping)
Disk 1 1 4 7 10 13 16
3N-2
(Disk Striping with Dedicated Parity Disk)
Disk 1 1 3 5 7 9 11
Disk 2 2 4 6 8 10 12
Striping
2N-1
2N
Disk 3 P(1,2) P(3,4) P(5,6) P(7,8) P(9,10) P(11,12)
N Blocks
• Each Block is 512 Bytes • Drive Capacity = 512 Bytes x LBA
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Other Drive Terminologies