SVM:
The main point of the SVM is to eliminate physical disk restrictions which can be done by enabling RAID (Redundant Array of Independent or Inexpensive Disk)
Types of RAID
1. Hard Ware RAID: It is basically a setup with a device called 'Disk Array' where multiple disks are connected and it doesn't depend on the software.
2. Software RAID: A software RAID can be done with a package called ODS which is also called as SVM.
- A software RAID is OS dependent
- In software RAID if the OS is crashed the entire RAID setup is disturbed.
Different kinds of RAID levels:
1. RAID - 0
i. Concatenation (sequential)
ii. Stripping ( alternatively & evenly)
2. RAID - 1: mirroring (simultaneously)
3. RAID - 5: stripping + parity
Meta Device:
A meta device is a logical device which is created by clubbing two or more physical disk.
State data base: It is a database that maintain RAID configuration and meta device information.
with out a STATE Data Base that RAID can't be configured.
1. RAID - 0:
i. concatenation:
1. min disk required = 2
max disk required = 32
2. Data will be written " sequentially" into '2' or more disk.
i.e. It first fills the 1st disk and then it will go automatically to 2nd disk and fill it.
3. read / write speed is normal
4. no fault tolerance
5. spanning is available
( the ability to write the data into multiple disk )
ii. RAID - 0 ( Stripping):
1. min disk required = 2 disk
max disk required = 32 disk
2. The Data is written alternatively and evenly into two or more disk
3. RW speed is faster
4. No fault tolerance
5. spanning is available.
2. RAID - 1 ( mirroring):
1. min disk required = 2
max disk (recommended) = 3
2. Data is written simultaneously into more disk
3. Read speed is faster, write speed is slower
4. Fault tolerance is available
5. Spanning is available
dis adv:
If data deleted in one disk the same data is deleted in other disk also.
How to take backup:
1. Detach & take online backup
2. If you write as any data in d2, e,f,g,h it will written in c0d0, but not in c0d1 because it is detached.
3. If i attach c0d1 resync occur, same data e,f,g,h, stored in c0d1 automatically.
4. If detached c0d1 take online backup, now c0d0 got crashed then no use of c0d1, so no resync, at this time we take 'mirror' (d3)..
3. RAID - 5 ( Stripping with parity):
1. min disk required = 3
max disk required = 32
2. Data is written alternately and evenly and the parity is written in other disk.
( in real time parity is included in A & B)
3. rw speed is faster
4. Fault tolerance is available.
5. Spanning available.
6. all the disk should be of equal size.
RAID - 5 (Striping with parity):
parity size = Total size of the disks / No. of disk = 90/3=30
= 30 /3 = 10 gb
(A+B+C) - parity size =90 - 30 = 60 gb
1. order to write the data alternate & evenly into two (or) more disks we need a Interlace value.
- By default the interlace value is 32 blocks (16kbs)
The main point of the SVM is to eliminate physical disk restrictions which can be done by enabling RAID (Redundant Array of Independent or Inexpensive Disk)
Types of RAID
1. Hard Ware RAID: It is basically a setup with a device called 'Disk Array' where multiple disks are connected and it doesn't depend on the software.
2. Software RAID: A software RAID can be done with a package called ODS which is also called as SVM.
- A software RAID is OS dependent
- In software RAID if the OS is crashed the entire RAID setup is disturbed.
Different kinds of RAID levels:
1. RAID - 0
i. Concatenation (sequential)
ii. Stripping ( alternatively & evenly)
2. RAID - 1: mirroring (simultaneously)
3. RAID - 5: stripping + parity
Meta Device:
A meta device is a logical device which is created by clubbing two or more physical disk.
State data base: It is a database that maintain RAID configuration and meta device information.
with out a STATE Data Base that RAID can't be configured.
1. RAID - 0:
i. concatenation:
1. min disk required = 2
max disk required = 32
2. Data will be written " sequentially" into '2' or more disk.
i.e. It first fills the 1st disk and then it will go automatically to 2nd disk and fill it.
3. read / write speed is normal
4. no fault tolerance
5. spanning is available
( the ability to write the data into multiple disk )
ii. RAID - 0 ( Stripping):
1. min disk required = 2 disk
max disk required = 32 disk
2. The Data is written alternatively and evenly into two or more disk
3. RW speed is faster
4. No fault tolerance
5. spanning is available.
2. RAID - 1 ( mirroring):
1. min disk required = 2
max disk (recommended) = 3
2. Data is written simultaneously into more disk
3. Read speed is faster, write speed is slower
4. Fault tolerance is available
5. Spanning is available
dis adv:
If data deleted in one disk the same data is deleted in other disk also.
How to take backup:
1. Detach & take online backup
2. If you write as any data in d2, e,f,g,h it will written in c0d0, but not in c0d1 because it is detached.
3. If i attach c0d1 resync occur, same data e,f,g,h, stored in c0d1 automatically.
4. If detached c0d1 take online backup, now c0d0 got crashed then no use of c0d1, so no resync, at this time we take 'mirror' (d3)..
3. RAID - 5 ( Stripping with parity):
1. min disk required = 3
max disk required = 32
2. Data is written alternately and evenly and the parity is written in other disk.
( in real time parity is included in A & B)
3. rw speed is faster
4. Fault tolerance is available.
5. Spanning available.
6. all the disk should be of equal size.
RAID - 5 (Striping with parity):
parity size = Total size of the disks / No. of disk = 90/3=30
= 30 /3 = 10 gb
(A+B+C) - parity size =90 - 30 = 60 gb
1. order to write the data alternate & evenly into two (or) more disks we need a Interlace value.
- By default the interlace value is 32 blocks (16kbs)
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