Error Creating VDEVs

Question

I am trying to create some new VDEVs on a DMX-4 and am receiving an error when running the command file through symconfigure using the prepare option.

The error is:
Error occurred while Validating
The symmetrix configuration does not contain sufficient memory

The command file contains the following:
create dev count=130, size=34556, emulation=FBA, config=VDEV;

The symconfigure command is:
C:\>symconfigure -sid xxx -file c:\symcli\create_vdev.txt prepare -nop

Any ideas? I couldn't find anything in the Sym Array Controls 6.5 or Symcli Command Reference 6.5 that indicating any other requirements or restrictions for creating the vdevs.

dynamox · Accepted Answer

decrease dev count just for giggles ..

AranH1 · Answer

What the? That worked I set it to 16 and tried again and it passed the validation. Why is that?

dynamox · Answer

i have at least 1000 VDEVs with 64G (mirrored) cache (DMX3 on 71). Quincy ...what are the requirements from cache perspective ?

dynamox · Answer

My hypers are 8.6G ..so that's probably why I can create so many ...plus I have more cache. Get out your check book man

Quincy561 · Answer

Each device needs some amount of meta data. Maybe the total amount of devices you added pushed you over the minimum cache requirement for the capacity.

AranH1 · Answer

Did you create them all at once? I had 417 on the array already and needed to add 130 more to get me through the next couple months. We have 48GB mirrored.

AranH1 · Answer

So the idea then is not the limitation in the ability to create a certain number at one time but a number that the array can manage in total?

Looks like you hit on the issue. I am unable to create more than the 35 I just created using another config session. So my DMX-4 maxes out then at 452 VDEVs? Is this something I can have my local CE change so that I can create more?

Quincy561 · Answer

I would be interested to see if at the end you can still create all 130 VDEVS as you originally tried to do.

AranH1 · Answer

My CIO will love that. He still complains about how much we spent on it 'You mean we spent a million dollars and can't create more virtual devices?'

AranH1 · Answer

So it must be my configuration. That is just surprising for a DMX-4 with 48GB of mirrored cache. I have a request out to my local service manager and CE to take a look at the box and see what needs to be done to create more.

AranH1 · Answer

Well it looks like 35 is the magic number of vdev devices I can create at one time. I kept on decreasing the number until it passed validation.

Oh well, guess I just need to run the create multiple times until the number of devices I need are created

Quincy561 · Answer

It is possible that you have reached the minimum user cache requirements for your system. If so, adding cache is probably your only option. Your local EMC team should be able to tell you if you need more cache or not to support the new configuration.

dynamox · Answer

I think I created in batches of 80 devices. I need to find my old symconfigure files.

Quincy561 · Answer

There are two factors that determine how much cache you need in the Symmetrix. One is the "performance" factor. This factor will depend on how many drives, what speed are the drives, and how many DAs are in the system. The idea is to have a the data stay in cache for some very small amount of time when the system is running flat out with random reads.

The second factor is the protected, or host addressable capacity. Every device you create will require some small amount of meta data to support it, including virtual devices.

AranH1 · Answer

Quincy,Thanks for the information. Is there a formula available to endusers that will allow me to calculate the required cache for the number of devices, disks, and protection scheme we have deployed or want to deploy? Or is this something for or CE to hand off to an architect?Thanks,Aran

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Error Creating VDEVs

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