SureStore E Disk Array 12H

[Jeffrey F. Goldsmith]

I have 2 questions about my disk array but only want to submit once. When I purchased my disk array it came with 8 9.1GB hard drives. They were setup as LUN0. Last year I purchased 2 18.2GB hard drives and installed them into the auto array and created LUN1. I was told that it would be best if I were able to install more of the 18.2GB hard drives. So, I have recently purchased 5 18.2GB hard drives to install into the disk array.
Here are my questions:

1. First, I am planning on installing 2 of the 18.2GB hard drives into the two open slots. After they are installed do I have to create another LUN(LUN2) or can I add to LUN1?

2. Second, I was told that I could replace 2 of the 9.1GB hard drives with 18.2GB hard drives. Are there any steps that I need to follow to ensure that I am doing this correctly? Will I end up with the additional space after the 18.2GB hard drives are installed? Do I need to modify my LUN0 as its size is now being increased?

I am sure that there are other questions that I need to ask so if there is anything that you would like to add please do so.

Thanks for the help.

[Trevor Roddam_1]

1/ You need to create a new LUN to use the added capacity.
Once created a LUN can't be extended and retain the data.

2/ This is a bit more complicated.
http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&locale=en_US&prodTypeId=12169&prodSeriesId=33733&prodSeriesName=hp+surestore+disk+array+12h&taskName=setup%2C+install+%26+configure&taskId=8414&prodSeriesId=33733&docIndexName=manuals
Is a link to the manuals.
You need to:
Ensure there is enough free capacity to remove the HDD.
Disable the HDD.
Remove the HDD.
Add the new HDD.

The admin guide is probably what you're looking for.

This is simpler said than done but is possible. One catch is if the configuration data for the array is on the disk you wish to remove. Then it becomes too complicated for this type of assistance and you may need to get someone in.

As always, backup and backup again before proceeding.

[Jeffrey F. Goldsmith]

At this point I have one of the hard drives setup as a hotswap drive. I lost a 9.1GB hard drive a couple of months ago and I had to remove the drive to get the disk array to continue working.
Does that mean that I have the space to remove the drive?
When I remove the 9.1GB and install the 18.2GB drive I know that it will rebuild the disk array which takes a couple of hours. Then if I remove the other 9.1GB hard drive and install the second 18.2GB hard drive and rebuilds itself again will I have the additional 18GB of space?

[Trevor Roddam_1]

By the sound of it the hotswap is in use supporting the dead drive.

Add two more 18GB HDD's into the free slots (11 & 12).

Once there are included in the array, this should be automatic if the auto include feature is on, replace the highest numbered slot with a 9GB HDD.

Wait for the rebuild to complete, this can be done through the mgmnt software (Admin and User Guide).

Then when all is rebuilt change the HDD beside it.

And so on until all HDDs are replaced.

The aim here is to keep equal number of the HDDs of the same side on each channel or side of the 12H.

As always backup multiple times before starting and if possible un mount all filesystems from the 12H.
A read of the Admin Guide will prove very enlightening. There are small pockets of information that are worth wading through the rest.

[David Bell_1]

Jeff,

1. Yes, you must create a new LUN. Once a LUN is created, it cannot be extended. Also keep in mind, you are limited to a total of 8 LUNS on the Model 12H disk array.

2. As already stated, you can replace the 9.1GB mechanisms one at a time and wait for the rebuild to occur. Once the rebuild is complete, you can then replace the second 9.1GB mechanism.

As stated, read the manuals, follow the noted procedures and get at least one backup prior to performing any of this.

Explaining the increased space is a little complicated, however, some general rules:
The overhead of the active hot spare will be as large as the largest disk or 18GB. The overhead for redundancy will depend upon your configuration and usage. The more available unallocated space you have the better the performance of the Model 12H to a degree. This allows for more RAID 1/0 space, hence better performance than RAID 5. As you begin to take up that space, more data is placed in RAID 5 and the performance decreases. Obviously when using RAID 1/0, anything above 50% utilization begins to use RAID 5 and performance will begin to decline.

HTH,

Dave

[Jeffrey F. Goldsmith]

I want to confirm my understanding of the information that has been given to me you wise ones.
Right now I have 8 9.1GB hard drives and 4 18.2GB hard drives installed in my SureStore E Disk Array 12H. I checked my disk drives with this command, ???arraydsp -a 0000000E0543??? and found that the drive information is on drives 1A and 1B.
So, after I backup my system on Saturday, I am going to be able to take out the 9.2GB hard drive in slot 4B and replace it with a 18.2GB hard drive. After it rebuilds it???s self I can then remove the 9.1GB hard drive in slot 4A and replace it with an 18.2GB hard drive.
After it rebuilds the system with the second hard drive installed will I have an extra 18GB???s in LUN0? What do I need to do now? Is there anything that I am missing?

[A. Clay Stephenson]

No, you missed the boat just a bit. Adding the extra drives (or swapping existing drives for bigger ones) will in no way increase the capacity of any existing LUN, after the drive swap and rebuild, your LUN's will be exactly the same. What will have changed is the amount of unallocated space. You can leave this space as unallocted and make the array faster by having more RAID 1/0 space OR you can use the additional space to create new LUN's.