topic Re: adding new vg to Surestore Array in Disk Enclosures

adding new vg to Surestore Array

Cesar Gonzalez_1 — Thu, 07 Feb 2002 18:10:03 GMT

Hi. I??ve got a Surestore Array E H12. I have attached the configuration showed by SAM.

Could somebody explain me what is the meaning of LUN (the manual is not clearly) and the way to add a new vg; when I do that with SAM, appears a message saying:
"Choosing a new set of disks will cause the previous set of disks, the disk configuration, and any new logical volume definitions, to be lost when you press "OK""

It sounds like a dreadful premonition of data loss...
and suspicious to do that.

Thanks in advance.

Re: adding new vg to Surestore Array

Helen French — Thu, 07 Feb 2002 18:52:41 GMT

Hi,

LUN ( logical Unit OR Logical Drive ) is a term stands for a disk partition. It can be a part of one hard disk or can be a collection of HDDs. Normally we don't use LUN partition in a single HDD nowadays. We use LUN for diskarrays now.

Suppose if you have 10 (10*4GB HDD) disks in a diskarray and you want them to be re-arrange to 3 different HDDs like this:

12GB - first LUN - 3*4GB
12GB - second LUN - 3*4GB
16GB - thrid LUN - 4*4GB

So that you can have 3 single disks of 12GB, 12GB and 16GB. These LUNs can be configured either through SAM or with diskarray utlities, which again depends on the RAID levels you need.

In your case the LUNs are already configured - 8GB, 16GB and 16GB. Out of these three, the first 16GB is already used ( vg01). Now you have 8GB and another 16GB free for creating more VGS.

For creating VG, select the LUN ( unused )u want and click action and create new VG. SAM will give you all help to configure your new VG and LVs.

I would recommend you to read the LVM, SAM and diskarray documents from www.docs.hp.com, before making any changes to the system.

A full backup of the system is always safe !

HTH,
Shiju

Re: adding new vg to Surestore Array

S.K. Chan — Thu, 07 Feb 2002 20:37:11 GMT

As long as you select the correct device (ie the "unused" ones) to create your VG you'll be fine. SAM just likes to prompt for confirmation or warning I would say, to make sure you know what you're doing.

Re: adding new vg to Surestore Array

Cesar Gonzalez_1 — Fri, 08 Feb 2002 11:58:30 GMT

Ok, but, are you sure I will not loss tha LUN??s configuration if I make that step...

Another cuestion more: Is it true that Disk Array can??t work with one of the three fans that have got (if the others two are off, I mean).

Thanks a lot guys. ;-)

Re: adding new vg to Surestore Array

Insu Kim — Fri, 08 Feb 2002 14:25:22 GMT

>Ok, but, are you sure I will not loss tha LUN??s configuration if I make that step...
The configuration map called NVRAM memory maps is saved to disk by successful shutdown.
It also located in both controllers and the disk drive modules.
NVRAM stores all configuration and meta data that map drive location information to real data.
The conclusion is that you're not going to lose NVRAM memory maps under normal circumstances but it could happen so taking a periodic backup is always important.

>Another question more: Is it true that Disk Array can??t work with one of the three fans that have got (if the others two are off, I mean).

Yes, in the 12H service manual,
The disk array enclosure is designed to ensure proper airflow with two fan modules operational, regardless of the number of disk modules installed. No filler panels are required for empty disk module slots. All three
fans must be installed for proper airflow.
If a fan module fails, an amber fan status light indicates that the fan speed is too slow or that the fan has stopped blowing air. A failed fan module has no airflow. If two fans fail, power will automatically shut
down to avoid overheating.

CAUTION: Do not remove a fan module
until a replacement fan is available. Also,
replace only one fan at a time. Removing two
fans at one time shuts down the power
module!
When replacing a fan module, do not leave a fan slot empty for more than ten minutes or a ???power off pending??? error will occur. When a fan slot is empty, the disk array will not be cooled properly. Without adequate cooling, disk module failures may occur.

In addition,
with 12H, up to 8 LUNs can be configured.
LUNs don't correspond to indivisual disks and groups of disks and when a LUN creates, it encompasses all of the included disks in the array, not specfic disks or groups of disks.

Hope this helps,
INSU

Re: adding new vg to Surestore Array

Helen French — Fri, 08 Feb 2002 16:31:34 GMT

Hi,

You won't loose any LUN information while creating a new VG. Be sure to select the 'unused' LUNs for creating new VGs. SAM will give you some notification/warnings before you create this. Read that carefully and make sure that you are using the correct one.

Also, If I remember right, in 12H diskarray 2 fans should work. The third one is the reduntant one. If any one goes off, you need to get it replaced as soon as possible. I have not seen any fan issues, so I am not sure, whether the diskarray will stop functioning if the fans are not working. See this for more hardware information:

http://www.hp.com/products1/storage/disk_arrays/midrange/12h/index.html

HTH,
Shiju

Re: adding new vg to Surestore Array

Cesar Gonzalez_1 — Mon, 11 Feb 2002 18:07:39 GMT

Thanks for all guys!!!!
Now I??m confident about make new LUN.