Sandip,

so i could potentially create 2 x 50G LUNs ..as long as i create in pairs of two and assign them to two different SPs (fibre channel) ..and Celerra will have no problems assigning them to specific pools based on underlying raid topology ?

That's correct - I am assuming that you are creating the LUNs on a supported RAID group configuration (if RAID5, it is either 4+1 or 8+1) - and of course select the Host ID (HLU) properly while assigning the LUNs to the Storage Group of Celerra.

Then Rescan the Storage either from GUI (easy) or from CLI and you will find 100 GB added to the respective Storage Pool.

I understand this is what Harold is also trying to do.

Cheers ---
Sandip

sorry Harold for jumping in ..i was just curious if that would work ..never had a chance to try it. Thanks Sandip

Hi Harold,

What I understand is that you are asking about whether you can have Host LUN and Celerra LUN on the same RAID Group. The answer is YES - you can create Celerra User (Data) LUNs on a RAID Group which has LUNs assigned to other hosts - except for the RAID Group that has Celerra Control LUNs. The (4+1) RAID 5 group where the Celerra Control (system) LUNs reside, must be all dedicated for Celerra only (no other host).

However, if you plan for creating Celerra User (Data) LUNs on a RAID group having LUNs for other hosts, the LUN configuration/rules/guidelines for Celerra needs to be followed - like for FC disks - it has to be of supported RAID group configuration (4+1 RAID5 or 8+1 RAID5, 4+2 RAID 6, 6+2 RAID6, RAID 1 etc) and create identical size LUNs and balance them accross SPs. For ATA LUNs - one or two LUNs on each RAID group owned by one SP only and so on. Also, please ensure to set the HLU (Host ID) for these LUNs while assigning them to Celerra Storgae Group. I understand, you are already aware of all these since you have done it many times in the past. However, if required, you may refer to the Release notes, Setup Guide, Support Matrix and other docs for more information if required.

Hope this helps.
Thanks,
Sandip

My pleasure - in fact this allows to utilize the storage more effectively, especially where the number of disks and/or the storage amount is very limited and needs to be shared by Hosts and Celerra.

However, no need to say sorry - your contribution is always welcome just like all others. We all are here to enrich ourselves

Cheers ...
Sandip

Hi Harold,

I was not very clear about the RAID configuration of the RAID groups from where you will be creating new LUNs - but now it is clear. However, unfortunately Celerra does not support other RAID configurations except the ones which are stated in release notes or Support Matrix. For FC RAID 5, supported configuration are only 4+1 or 8+1 RAID groups. If you create LUNs from any other RAID configuration like 3+1 or 4+1 RAID5, I don't know whether that will work - definitely AVM will not recognize them, but you may get the disks in the celerra for manual configuration - but even if you manage to get it working, it will be an unsupported configuration.

That's my understanding - request others in the forum to comment or suggest if any.

Thanks again,
Sandip

Sandip,

Great response, but I was asking the question from a slightly different point of view. I wanted to know if I could a add a LUN into my Celerra Storage Group that would not be part of the existing pools and that could be allocated manually. My current R-5 groups in the pool are 8+1 but I was hoping to be able to drop LUNs from different structrues (3+1, 4+1, etc.) into the Storage Group and then be able to use the file systems (not pools.)

Probably not making myself understood very well, but I value your help and thoughts.

Thanks,
Harold

thats differently - no matter if its a gateway or a NS Integrated you have to stick to the supported RAID group types and sizes

In short for RAID5 its 4+1 or 8+1 (maybe 6+1)

Technically you wouldnt expand the any of the clar_* pools - these are system pools and they work a bit different from user-defined pools.
WIth system pools the Celerra automatically pulls eligable (i.e. correct RAID group and size) LUNs into the pools and stripes them for load-balancing.

You should not (and I believe cannot extend) a system-defined storage pool - nor do you have to because it will automatically extend.

Now what you can do is to manually extend a file system with storage from a different pool. We do print a warning there - you have to be aware of potential performance difference.

For example if you have a file system based on RAID5 and extend it with some space from a RAID1 pool it will work - but you can see differing performance for parts of the files , depending in which area they got stored.

In your case I would recommend to at least find some space on 4+1R5 raidgroups and use that to manually extend your file system.
It would be better through from a performance point to try to match the striping of your existing file system - i.e. if your fs got striped onto 4 LUNs try to extend with stripes of 4 LUNs

hope that makes it clearer

of course that isnt just black-and-white - we try to configure providing the best performance - but sometimes when you dont have enough disks free compromises get made

Physically, it can be done, but it would be unsupported.

Plus, what would you do with this odd-RAID LUN? You couldn't use it to expand existing filesystems, because once the data crossed the boundary between RAID types, performance would literally tank.

We only support a few of the RAID types that CLARiiON is capable of making. It is physically possible to create others, but you'd be placing yourself in an unsupported configuration.

Message was edited by:
BillStein

yes, you can do that because you are using a Celerra gateway

If you had a true NS Integrated model like the NS700 then you would be supposed to stick to the DAE templates as configured by setup_clariion