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How long take to restripe CMC RAID

woody140284
Occasional Contributor

How long take to restripe CMC RAID

Hello,

 

We are about to add some new disks in to our 2 server VSA set up. I understand that I will need to extend the Array and then create new Logical Drives, which I will present to the ESX and then add to the VSA. I am guessing this will take a couple of days to extend, but should ultimately go ok. 

 

What I need some advice with is, once I have presented the drives to the VSA and then show up in CMC as unitialized, then choose "Add disk to RAID", 1, can I add multiple disks at the same time and 2, how long is it likely to take to restripe to data over these new disks?

 

Any help would be great

 

Thanks

 

Carl

6 REPLIES
a_o
Valued Contributor

Re: How long take to restripe CMC RAID

Are you describing dynamically adding or extending the storage the VSA sees?
Are you using VMDKs or passthrough disks?
AFAIK, what you're asking can't be done in the manner you're describing.

The following is based on my hands-on experience with VSAs in ESX and HyperV - SAN/iQ >V10.

A VSA's consists of at least 2 'disks' passed from the underlying VOSE (underlying storage to the VSA) - either in the form of VMDKs, VHDs or Pass-through disks.

These are 1, the 'Configuration' disk and 2, the 'Data' disk.
These disks are defined in the underlying Linux OS that Lefthand OS is based on. The 'Configuration' disk should not be touched.

The 'Data' disk can be extended in the manner you describe, but you'll probably lose all of the data on the VSA. This is not a problem per-se, as long as you have your volumes with the proper Network RAID in SAN/iQ.

Extending the underlying hadware array will not necessarily extend the disk as seen by Lefthand OS. (The extents of the disk would not have changed.)

Once you've presented the new disk to the VSA, it is seen as just a raw disk by Lefthand OS. Essentially, a new 'disk' is created in Lefthand OS.

You would have 'Re-configure' the RAID for the VSA in the CMC at this point,
After this, you'll have an empty SAN/iQ array, reflecting the new size of the underlying storage.
It can now be re-striped with the Network RAID based on the volumes you've created in SAN/iQ.
The Network RAID type, size and qty of your volumes will determine how long it will take to re-stripe.

ssuhail
Occasional Advisor

Re: How long take to restripe CMC RAID

I have a 3 VSA cluster. I am adding disks to the VSA, so that i can increase the SAN size. I can see the disk as unintialized in each of the VSA.

 

Do i have to follow the below steps

 

  1. Remove the VSA from the management group.

 

  1.  In the CMC, re-configure RAID on the VSA.

 

 

  1. Add the VSA to the existing “CHENMGMT” management group and “CHEN-cluster” cluster. And once VSA is reinserted, will there be any indications that it has successfully spread the data to this newly inserted VSA.

 

  1. Repeat these steps one at a time for each of the three VSA.

Thanks

a_o
Valued Contributor

Re: How long take to restripe CMC RAID

I don't understand your scenario.
Have you added the extra underlying storage already?
Or, are you about to add them?

 

If you already see the disks as unintialized in the VSAs.

All you would need to do is just reconfigure RAID on each of them.

The extra storage will become available to the cluster as you add them to each VSA node.

 

For instance, after you've added storage to VSA#1, your additional storage in the cluster(above what the nodes had originally) will be good for NR0.
Then, after you've added storage to VSA#2, your aggregate additional storage (2 nodes ) will be good for NR1 in your cluster.

And finally, after you've added storage to VSA#3, your additional storage will be good for NR5.

ssuhail
Occasional Advisor

Re: How long take to restripe CMC RAID

My scenario is

 

3 VSA

 

for each VSA there are existing two disk presented of 1.6TB. I have active data on them. The volumes are in NR-10 protection.

 

I want to expand my cluster size, so i have added disks on the storage blades. I have now 2 new disk with 1.6TB on each of the VSA. They are in "uninitialized" status.

 

I have attached screenshots which wil help you understand better.

 

Thanks.

 

a_o
Valued Contributor

Re: How long take to restripe CMC RAID

Still unclear. What's your LH/SAN I/Q 'physical' raid setup?

 

In any case, it depends on what you really want to do.

 

A stab in the dark: (I've not done it this way before, but it should work.)

 

Select one of the new disks - i.e VM0102,  then in the "Disk Setup Task" select "Add Disk".
If the new disk now shows as "Active", you should be set. This disk should now be part of your raid set.
Otherwise, add the other disk (VM0103) and create a new RAID set in the "RAID Setup" tab, using VM0102 and VM0103.

Rinse and repeat.

a_o
Valued Contributor

Re: How long take to restripe CMC RAID

After looking at your screenshots again, I see that your LUNS are using NR10 with a 3 node cluster.
I think Re-configure raid is all you need to do, as your volumes should stay on-line even if you reconfigure the raid for one of your VSA nodes.