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Need to add disks in the newly installed disk shelf to the existing aggregate.

Hi Techies,

 

We have a cluster with 2 nodes and running on data ontap version 8.3.1 c-mode.

 

We have two SAS aggregates hosting on each node and raid group size is 17.

 

We have installed new disk shelf with 24 drives. I want to add the new disks to the exising aggregate. But with the current raid group settings i can able to add only 17 disks to the existing aggregate. Remaining 7 drives will be not used.

 

I don't want to waste those disks as spares, what i am planning is i want to change the aggregate raid group size to 20 and add the 3 disks to the existing raid group and create a new raid group with 20 disks.

 

Please suggest me how to proceed with this.

 

 

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Go into advanced or diag mode

 

run this

 

storage aggregate show -fields maxraidsize

 

that will show you the size

 

storage aggregate modify ?  

 

Follow the settings.  

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Hi @JGPSHNTAP

 

 

Thabks for the commands, I know all the commands. I am looking for best practices not commands.

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

This statement "Please suggest me how to proceed with this"

 

Let me to post the above.

 

 

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

[ Edited ]

The first thing you do is modify the raid group size and then add the drives.  

 

and you cannot undo so make sure you do it right the first time

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Hi @JGPSHNTAP

 

 

Sir, i have already mentioned the raid group size also in the post. Anyway thanks for your reply ... Smiley Happy

 

I will take care of it.

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Hi @JGPSHNTAP

 

I know the process and commands. I am looking for best practice. thank you ... Smiley Happy

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Not once in your post did you ask for best practice to add drives.

 

If you are looking for SAS, 24 is a good number.  

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

RAID group sizing is always a littel awkward, but you are basically looking for good logical splits.

 

as one of the responses mentioedn 24 for SAS is not a bad idea, but as you've said it's really about logical bounderies.

 

nothing wrong with your original idea, make it 20.. add three drives and then a new RG of 20 and add them to aggregate is all fine.

 

personally i try to keep my boundaries to shelves.. hence 24 a good number, so if i add a full shelf, i'm getting the optimum capacity without drives getting left over.

 

there are some suggestions around whether you want capacity or resillience, so smaller RG's provide less performance, but in the event of failures have quicker rebuild times etc... but often these aren't huge considerations.

 

one thing you didn't say was you current setup.. so two 17 drive aggregates, so what is that 36 disks, with 17 in RG's and a couple of spares?

 

not sure if this all helps.. but your original plan is solid enough, just think of next time you add a shelf.. you'll end up with a similar problem.

 

 

Re: Need to add disks in the newly installed disk shelf to the existing aggregate.

Hi @JGPSHNTAP

 

Sir,

 

I have not asked for commands. Please go through my post, i have explained my plan also.

 

Thanks ... Smiley Happy