Anyone here know RAID levels pretty well? I'm wondering if RAID 10 is the same as RAID 0/1???

 

RAID 10 = RAID 1+0

Also check out http://www.anandtech.com/guides/viewfaq.html?i=110 for the basics in RAID definition.

 

RAID 10 is a striped RAID which is mirrored.

I've never heard of 0/1.

:inquisitive:

 

No, it's not. Raid 0 (not 01) is striping. Raid 1 (not 01 or 10) is mirroring. Raid x/y is BOTH, applied in different configurations. Let's say you have 2 different file-systems (volumes in Veritas terminology) striped on 2 different disks. There are TWO different ways you can mirror this configuration with 2 addition disks

1) You mirror each VOLUME stripped on two other disk. Raid 0/1
-or-
2) You mirror each original DISK to another DISK. Raid 1/0


The advantage of #1 is the entire volume is mirrored as a logical "unit" by your raid manager.

The advantage of #2 is that if you lose a disk ONLY the failed disk is rebuilt from the mirrored pair, NOT the entire volume. However, the disadvantage of #2 is you don't have to mirror (you can FORGET to mirror) the other disk and your striped volume isn't really mirrored!!!

So basically, raid 0/1 or 1/0 is a trade-off between speed of recovery and simplicity of volume management. There should be no difference at all in speed during normal operation mode.

http://www.veritas.com/products/listing/Pr...lumemanagerunix

 

RAID 0 is Striping
RAID 1 is Mirroring
RAID 3&5 are N+1 redunancy Raids. Meaning you have 1 extra drive to be used as a failsafe incase of drive failure. The difference between 3 and 5 is: 3 uses 1 fixed drive for its parity. 5 rotates parity between the drives.
So if you have 4 drives. (D=data, P=parity)
Raid3 would write DDDP, DDDP. DDDP. Always writing the parity data to the same drive.
Raid5 would write DDDP, DDPD, DPDD. Rotating the parity between the drives.

Now you can combine raid levels.

Raid 10, 1/0, 0/1 are all the same thing. Striping & Mirroring.
Raid 50, 5/0, etc would be multiple Raid5's that have been stripped.
Raid 51, 5/1 etc would be a mirrored pair of Raid5's

Make sense? Anymore questions?

 

You forgot two and four. Not that they are ever implemented, but its important to know.

 

[QUOTE]Originally posted by krazik
[B]

Now you can combine raid levels.

Raid 10, 1/0, 0/1 are all the same thing.

 

There are also subtle differences between RAID configuratins according to vendor. RAID 10 (0+1,0/1,1/0... etc.) Simplified... RAID 0+1 is two sets of mirrored drives striped across one another, it provides for good data though put and thus the reason that many database applications use it (ie. Progress). The biggest drawback is that you loose half of the total drive space due to redundancy. Depending on vendor... they may configure this array set up with slight differences.

 

You don't want your RAID level too high. Over expose to RAID can cause illness even death.
Do not spray closer than 12 inches.
If ingested seek immediate medical attention.

 

[QUOTE]Originally posted by S2K
[B]

Thanks for everyone's input.