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EVA VDISK Creation takes hours

 
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gstonian
Trusted Contributor

EVA VDISK Creation takes hours

I raised a call with HP but never got a satisfactory so thought I'd post here in case their were any other opinions out there.

Over the last week or so, simple vdisk creations can take an extra-ordinary amount of time to create (Over 6 hours). One afternoon, a vdisk creation (250GB , Raid 5) took over 6 hours to create. Others have been taking 2-3 hours.

HP's response was that actions like Vdisk creations/deletions & levelling run secondary to I/O demand which takes priority so can sometimes take longer.

However if you look at the stats from evaperf when I tried to create the vdisk (15thApr@10:30am) the eva hardly seems stretched to the limits.

We perform business copy refreshes every day and as a consequence, some of our disk groups are pretty much constantly levelling. Now what seems a bit of a coincidence is that whenever we have this problem with a long vdisk creation time, one of of Disk Groups has a levelling state of "pending".

Would a vdisk creation request queue behind a pending request such as levelling ? I've created several disks when a levelling process is uinderway with no problem. The disk creation is on a seperate disk group from that which is levelling. I have seen this scenario a couple of times now to suspect this may be the case.

Does anyone know causes Disk Groups to have a pending status when it comes to levelling ? And could other requests queue behind this pending action?

i.e.

Leveling state: Pending
Leveling progress: 0% 100% 0% leveled
7 REPLIES 7
IBaltay
Honored Contributor
Solution

Re: EVA VDISK Creation takes hours

Hi,
I have seen the disk ungroup blockage in a situation of no free space. The spare space had to be used there. In that situation the single disk protection (2 spares) turned into none and the ungroup was blocked by the undone leveling. Do you have enough free space in your EVA during the blockage occurances?
the pain is one part of the reality
OFC_EDM
Respected Contributor

Re: EVA VDISK Creation takes hours

Check your occupancy levels.
We don't go over 80% as that's recommended.
As well as keeping 2 spares.

I've seen slowness when creeping above the 85% mark.

So I agree with the previous post..check your space.

Cheers
The Devil is in the detail.
OFC_EDM
Respected Contributor

Re: EVA VDISK Creation takes hours

Forgot to mention the following in case it ends up not being occupancy related.

You may want to get support to dig deeper into your RSS groups and how they're spread out across the disks/shelves.

What model do you have? How many shelves? What type of drives? Speed of drives?
Are there any warning lights on the EVA?...specifically back of controller.
The Devil is in the detail.
Amar_Joshi
Honored Contributor

Re: EVA VDISK Creation takes hours

As mostly covered by replies, adding some thoughts to it:

Levelling has many different stats, levelling when the new disks are added/removed from diskgroup, levelling when new vdisks are created/deleted and leveling when disk is failing. Some of these takes very short and some takes days. If an intense levelling operation is co-exists with a vdisk creation, first it will restart the levelling as soon as the vdisk is created and will make the next relevelling more intense. With my personal experience (on old EVA500) if this is done repeatedly, at one point the levelling got hung and didn't move for weeks. It was very unstable few years back but hopefully with new XCS it should have been better.

Nevertheless, best practice is to not to restart the levelling by any means if it started once and part of this is that one should create the vdisk one at a time.

If you have come to the point where every relevelling takes loooong time, you are gonna seek HP expert help on it. I am sure you will find a right guy to understand your situation.
gstonian
Trusted Contributor

Re: EVA VDISK Creation takes hours

Thanks for your responses.

Most of the levelling is triggered by the business copy deletion/refreshes that happen daily, primarily on a DG that is only 80% full so suspect we're just stuck with the way things are just now..
Amar_Joshi
Honored Contributor

Re: EVA VDISK Creation takes hours

Looks like you are using old EVA3000/5000 and it may not have a CONTAINER feature. New EVAs have this feature and that can save you from deleting the BC VDISKs everyday.

Again, personally I felt that it's a killing way to create and delete the volumes everyday, which triggers the levelling on DG. Since you can't do anything about it, consider other options when time/budget permits you to avoid it happening on the storage.

My 2 cents worth.
gstonian
Trusted Contributor

Re: EVA VDISK Creation takes hours

Thanks for your responses.

Looks like I'll just have to live with things the way they are just now.