How to know RAID level ?

[Deepu Chakravarty]

How to know what RAID level of our HP-UX system is configured ?

We have one to one mirroring of disks.

[Shaikh Imran]

Hi,

Do you have a RAID Array device of just a mirror DiskUX installed ?
If you have only mirror disk installed &
one-one mirroring then the disks can be considered as in RAID 1 .But, this is therotically contradicts with the RAID concept where you have to have an array,as the full form of RAID implies.

If you have a RAID array Device then

amdsp -a or ammgr or arraymgr etc.., commands could help .
or also sam will do the job.
OR
some devices display the RAID level in ioscan also, aloong with the Disk device file names.

Regards,

[Deepu Chakravarty]

Hi,
I can say that I have configured one-to-one disk mirroring. May be theoritically it is RAID 1. But is there any command at system level to know the RAID level ?

[Shaikh Imran]

Hi Deepu,

Now your quetions becomes
"You want to know whether yor disks are mirrored or not "

first is you find out whether mirror disk is installed on you system or not by
#swlist
you will get something like this along with other softwares installed.

B2491BA B.11.00 MirrorDisk/UX

Second is lvdisplay /dev/lvpath
this will tell the number of mirror copies
you have made for this logical volume...
Lvols are mirrored then your disks are mirrored
Hope this helps...

Regards,

[Deepu Chakravarty]

Hi,
Imran,
My question is not changed. I know I configured one-to-one disk mirroring. But I want to know whether this is called RAID 1 or there is any command at system level to know the RAID architecture.

I hope u understand me now.

[Sunil Sharma_1]

Deepu,

HP UX LVM support only level 0 and level 1 of RAID. For checking what level of raid is implimented you can use lvdisplay -v command and in output check the field "Mirror copies" if it's value is 0 means no mirroring and if 1 or 2 it means 1 way or 2 way mirroring. For knowing about RAID 0 you have to see field "stripes and stripe size" in output of lvdisplay commans.

Sunil

[Deepu Chakravarty]

Hi Sunil,

Your input seems to be good and quite explanatory.

lvdisplay -v of one lvol shows Mirror Copies 1 and Stripes and Stripe size 0. Does that mean no RAID implemented ? Only 1-way Mirroring ?

[Ted Buis]

1-way mirroring means one additional copy of data, while 2-way mirror means two additional copies (3 total) of the logical volume. MirrorDisk mirrors logical volumes not disk drives.

[Rainer von Bongartz]

What you call '1-way Mirroring' is RAID 1

Regards
Rainer