DJohnsonRose Member Posts: 55 ■■□□□□□□□□
Can someone explain to me what RAID 2,3 & 4 are please? I have tried using CBT nuggets and online materials but i can't seem to get my head round it? Also can someone explain to me the difference between RAID 10 & RAID 1+0/0+1, I have looked on iSCSI RAID Switch, External SATA RAID, vmWare Storage-NAS Network and SAN Data Storage Solutions with JetStor but it looks the same asides from the blocks being copied in a different order. What difference does it offer when you measure the I/O or throughput?Any help would be greatly appreciated as I am taking this exam next week!Thanks in advance guys
Raid 2 / 3 / 4 is a explained a bit better here and here.
Main difference in certain Raid levels is how data is striped - it can be BLOCK based or BIT based ... easy to miss (the difference that is), which might make it confusing at first.
I have never taken this exam, but I am working in IT for 15 years now and I never came across a Raid 2, 3 or 4 impolementation
Edit: forgot I DID take Server+ as an early beta .... lol
Future Certifications: CCNP Route Switch, CCNA Datacenter, random vendor training.
I typed all this info and then ran across this site - quick and dirty RAID info: Basic RAID Organizations
Stripes across all disks in an array using all available drive space
Maximizes space and improves read/write performance
Duplicates data from one disk (or set of disks) to another disk (or set)
**Requires 39 disks - 32 disks for data, 7 disks for error-recovery code
RAID 2 system would normally have as many data disks as the word size of the computer, typically 32
With 32 data disks, a RAID 2 system would require 7 additional disks for ECC
Data is interleaved at a bit level and can withstand losing 4 error-recovery drives without affecting data
RAID-3 and RAID-4
Data striped across a variable number of drivesHas a dedicated parity drivethat can be used to reconstruct data from any single crashed data driveRAID 3 utilizes byte level parityRAID 4 utilizes block level parity
Stripes data and parity calculations at the block level across all drives
Parity information is interleaved
Disk reads and writes are performed concurrently
No dedicated parity drive
Extends RAID 5 by adding a second parity block distributed across member disksYour array can lose two drives without data loss - protecting against data loss during a rebuild of a failed driveThere is a performance hit for write operations as two parity operations are written across the array
Identical to RAID 5 but array functions as a single virtual disk in hardware