Solaris

Hi ,

I am new to SVM .when i try to learn RAID 1 , first they are creating two RAID 0 strips through

Code:

metainit d51 1 1 c0t0d0s2

metainit d52 1 1 c1t0d0s2

In the next step

Code:

metainit d50 -m d51
d50: Mirror is setup

next step is

Code:

metaattach d50 d52
d50 : submirror d52 is attached

Please guide me what is the mirror and sub mirror. i knew the RAID 1 concept but i like to know the difference between mirror and the sub mirror and one way mirroring , two way mirroring.

Thanks
MaroV

in your example d50 is the mirror, d51 and d52 are the sub mirrors.

d51 and d52 are meta-devices that reference the real slice on the disk. d50 is the meta-device that references both sub-mirrors, d51 and d52. Read/write actions go to d50, SVM then applies the read/write to both sub-mirrors at the same time thus maintaining the RAID1.

You should not mirror slice 2.

Can any one can guide me what is sub mirror and how its differ from mirror in RAID (SVM)


Thanks
MaroV

the mirror (top device) contains sub devices. thats all...

for example:

Code:

d0--d10
 |
 ---d20

d0 = top device = mirror
d10/d20 = sub devices = sub mirror

Some more explanation from the above diagram:

d0 - a meta device (logical device), this is the actual mirror we use to store the data.

d10 & d20 - these are the sub-mirrors formed by two different slices.

The writting is done in d0 but physically, d0 writes the data into two sub-mirrors (d10 & d20 ). When we perform any kind of operation with this raid device, we only point d0.
Means, d0 is the actual raid device we refer.

- d10
-
Writting to ---------- d0 -
-
- d20

Please write if this is still unclear to you.

Thanks,
Deepak Tiwari

For your reading and understanding
:- Solaris Volume Manager Administration Guide - Sun Microsystems