MSA Storage

Adding new drives to MSA 1500

 
Chris Boylan
Occasional Advisor

Adding new drives to MSA 1500

I'm new to the HP StorageWorks devices and need some clarification. I have an HP MSA 1500 attached to a VMware ESX server. I have added two new drives to the MSA box. Do I need to expand the array, expand the LUN that my ESX server uses, or something else?

I only have CLI access (unless someone can point out another way of doing this).
13 REPLIES 13
Uwe Zessin
Honored Contributor

Re: Adding new drives to MSA 1500

You can expand the disk drive array (but it will be _slooww_ or create a new one. Once the disk drive array has been created, you can expand the logical disk or create another one provided that you did not hit the limit of 32).

As of today, you cannot expand the VMFS partition, however, you can use the VI-Client to add a VMFS extent. That is possible up to 3 times on the same LUN, because the VI-Client creates primary partitions for the extents.

Many people are shy of VMFS extents, because their management requires some care: e.g. extent(='add storage') from ONE ESX server, but ONLY 'rescan' on all remaining ones.
Again: do NOT attempt to 'add storage' from multiple servers !!!

There is nothing wrong with CLI-only access to the MSA1599cs - as far as I know, it is not supported to install ACU in the service console.
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Chris Boylan
Occasional Advisor

Re: Adding new drives to MSA 1500

Thanks for the fast reply. This may be painful - I'm a total newb with this process and have been thrown into the deep end. I donâ t want to drag you into a discussion about how to make the new storage available to the ESX server (although I appreciate that info as well), I just want to focus on adding the new drives to the MSA 1500.

Here are the drive assignments:

Disk List: (box,bay) (B:T:L) Size Speed Units
Enclosure 1: SCSI (0:06:00) PROLIANT 4LEE CP20
Disk101 (1,01) (0:00:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4
Disk102 (1,02) (0:01:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4
Disk103 (1,03) (0:02:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4
Disk104 (1,04) (0:03:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4, 5 (spare)
Disk105 (1,05) (0:04:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4
Disk106 (1,06) (0:05:00) 146.8GB 160 MB/s 0, 1, 2, 3, 4
Disk107 (1,07) (0:08:00) 146.8GB 160 MB/s 5
Disk108 (1,08) (0:09:00) 146.8GB 160 MB/s 5
Disk109 (1,09) (0:10:00) 146.8GB 160 MB/s 5
Disk110 (1,10) (0:11:00) 146.8GB 160 MB/s none
Disk111 (1,11) (0:12:00) 146.8GB 160 MB/s none

Disks 10 and 11 are the new drives. The ESX server - where we need the additional space - is attached to LUN 4. You're telling me that expanding the whole array will take a long time (which I expected) but can you estimate how long? By doing so, do I then have to expand the LUNs to take advantage of the additional space, or will expanding the array distribute the new space to all LUNs?

How would I add a new array? Since I only have two new drives, does this mean that I cannot configure the new array with RAID 5? Or are the terms "array" and "LUN" interchangeable in this context?
Mark Wibaux
Trusted Contributor

Re: Adding new drives to MSA 1500

An "array" for a MSA1500 is just a bunch of disks in a group. A "LUN" is is what you create within an array and is what you present to a host.

I've attached the CLI guide.
Page 33 has the command to expand an array.
Page 34 has the command to extend the individual LUN once the array has been expanded by the previous command.
Mark Wibaux
Trusted Contributor

Re: Adding new drives to MSA 1500

Oh I meant to say. Looking at your drive listing you appear to have 2 "arrays".
ArrayA is drives 101,102,103,105,106
ArrryB is drives 107,108,109
And drive 104 is a global spare for both arrays.

Also make sure you double check the LUN number you want to expand as LUNs can either start at 1 while "units" start at 0 OR both LUNs and units can start at 0.

If you want to make sure you are getting the right one do a "show unit x" for each unit number and check its size versus what you see in Virtual Centre.
Sivakumar MJ._1
Respected Contributor

Re: Adding new drives to MSA 1500

VM-MSA1500 Whitepaper.
Chris Boylan
Occasional Advisor

Re: Adding new drives to MSA 1500

Perhaps I should back up and explain my situation. My boss wanted more space available on the SAN to the ESX server so he ordered two drives and asked me to install them. This is my first experience with SANs and ESX so I am completely lost. Uwe mentioned that I cannot expand the VMFS partition and suggested the use of an VMFS extent. VMware best practices state that for optimum performance of a VMFS LUN, one "should aggregate the total I/O throughput for all applications/VMs that might run on a given shared pool of storage, then make sure you have provisioned enough back-end disk spindles (disk array cache) and appropriate storage service to meet the requirements."

So, would the best approach then be to expand Array A - since that is the one that has the most physical disks attached to is, as well as having the LUN (unit 4) where the ESX datastore resides - and then create a VMFS extent? How would I go about making this new space available to an extent? Or should I take that question elsewhere?

I also need some clarification on the "expand unit" command. If I understand the CLI guide correctly, I must include all of the current disks in a unit when expanding it, including the new disks. If I wanted to expand unit 4, and unit 4 is using Array A, I should enter the following command:

expand unit 4 "disk101-disk103 disk105-disk106 disk110-disk111"
Mark Wibaux
Trusted Contributor

Re: Adding new drives to MSA 1500

You only need to specify the disks you want to add not the existing ones.
Once you add the disks to the array you then need to expand the LUN.
Once you have expanded the LUN you should do a storage rescan on each of you ESX host machines. Once that is completed, choose one ESX host and add an extent to the datastore you need to expand. Once this is completed the other ESX host will automatically pickup the new size (DO NOT try to make the same extent change on multiple hosts). This might take a while to appear in the Virtual Center console.
Chris Boylan
Occasional Advisor

Re: Adding new drives to MSA 1500

Almost there...

When I enter this command:

expand unit 4 disk110-disk111

I receive the following error:

Unit expansion failed. You have to include all the current disks in the unit when expanding.

If I issue the following command:

expand unit 4 "disk101-disk103 disk105-disk106 disk110-disk111"

I receive the following error:

Missing disk-list. Example: "disk101 disk112-disk202 disk314"
DISKxyy: x={1,2,3} (box #) / yy={01-14} (bay #)

Looks like a vicious circle to me.
Chris Boylan
Occasional Advisor

Re: Adding new drives to MSA 1500

It finally worked by using the following command:

expand unit 4 disk101-disk103 disk105-disk106 disk110-disk111

Apparently, adding the quotes is what caused the error, but the documentation showed quotes in its examples.

Thanks everyone for their help!