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MSA 2040 presenting one large volume

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jokken
Frequent Visitor

MSA 2040 presenting one large volume

hi all,

we have a MSA 2040 and a second shelf. 48 drives in total. We are using the Storage Management Utility to configure the disks.

We have created three 16 drive vRAID-10 1 disks. Each vdisk has one volume. Right now each volume shows up as an extent (mount point/share) on the fiber channel network.

is there any way to show these 3 volumes as 1 large virtual volume?

i could change the vdisks to a different RAID so one volume would have more disks. But a single vdisk is not able to have all 48 drives in it. so i would have the same question with 2 volume rather than 3.

any help or comments would be appreciated!

9 REPLIES
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jokken
Frequent Visitor

Re: MSA 2040 presenting one large volume

i should clarify that:

this basically is creating one large volume out of multiple vdisks.

is this possible?

thanks!!

HPSDMike
Valued Contributor
Solution

Re: MSA 2040 presenting one large volume

Yes, likely possible but probably not without loosing the data you have on the vdisks/volumes. The MSA 2040 includes the ability to use virtual storage instead of linear storage. You would add your vdisks (regardless of their RAID config) to 'Pool A'. This creates one large storage 'pool'. From there, you can create a volume out of the pool (or multiple if you wanted). The size of the volume can be as large as the MSA or VMWare maximums. The maximum LUN size for the MSA is 128 TiB. You will ideally want all the vdisks, in the pool, to be configured with the exact same set size and RAID type (which it sounds like you may already have). Note that, by adding everything to 'Pool A', this essentially means that controller B is doing nothing more than standing by for a failover situation. In a perfect world, you would have all your vdisks spread amongst both Pools A and B so that both controllers can be 'working' at the same time. This would defeate your goal of trying to get this as one large volume. Note that the extent method, you are already using, may be totally approriate in many cases. Make sure you're using the latest firmware GL220P009. 

Reference 

https://www.hpe.com/h20195/v2/GetPDF.aspx/c04123144

https://www.hpe.com/h20195/v2/GetPDF.aspx/4AA4-6892ENW.pdf

 

I work for HPE. The comments in this post are my own and do not represent an official reply from the company. No warranty or guarantees of any kind are expressed in my reply.
jokken
Frequent Visitor

Re: MSA 2040 presenting one large volume

thanks HPSDMike. that was exactly what I needed!

i needed that firmware upgrade and I also needed to use the newest version of the storage management utility, v3. this was an available via a link at my v2 login prompt. (i knew about v3 but never used it until now, it is a better interface overall...)

thanks

HPSDMike
Valued Contributor

Re: MSA 2040 presenting one large volume

So glad this helped you out. If you decide to move to RAID 5 or 6, be sure to follow the "power of 2" rule detailed in the best practice document. This will give you the best possible performance. 

Take Care,

Mike

 

I work for HPE. The comments in this post are my own and do not represent an official reply from the company. No warranty or guarantees of any kind are expressed in my reply.
jokken
Frequent Visitor

Re: MSA 2040 presenting one large volume

 hi again,

i have a follow up question not totally related to  my original. But I thought this would be a great place find some expertise.

So I now have this large 7TB volume on the fiber channel network (thnks to HPDSMike). I have it mapped to multiple (14) servers via fiber channel each server on it's own lun-# mapping.

I'm told that this is dangerous. unless I have the right filesystem installed on this volume I will get data corruption (if using a non cluster/distributed filesystem like ext4/xfs). So I need to find the right filesystem to put on this single volume so I can use it from multiple servers at once.

many of the filesystems I've seen that are meant for this use are filesystems that require a management/clustering server to maintain. (ie CEPH OSDs). 

say if I were to use CEPH, the IO then becomes over ethernet, and not over fiber channel which defeats my infrastructure.

does anyone know is there a filesystem I can put on this volume which can be accessed by multiple servers via fiberchannel that doesn't require any management server, and can just be created and used?

also will data corruption occur if I do use ext4/xfs and can ensure each server will only write to directory designated for it only, and never write where another server is writing?

(this won't be used as a file server for people to be doing unpredicatable writes to, but it will be used for a specifc predicatable location for 14 openstack computes node to write vHD disks to)

thanks for any input you can provide!

 

 

Dennis Handly
Acclaimed Contributor

Re: MSA 2040 presenting one large volume

>also will data corruption occur if I do use ext4/xfs and can ensure each server will only write to directory designated for it only, and never write where another server is writing?

 

Yes.  The only way this can work is if each host can only write to separate parts of the volume.  I.e. carve the volume into sub LUNs.  Otherwise, how will each host know where the other hosts are writing/reading?

Separate directories in a filesystem aren't good enough.  Where is the file system going to get a new block of storage?

(Either for data or for the metadata.)

 

> this won't be used as a file server for people to be doing unpredictable writes to, but it will be used for a specific predictable location

 

This could only work if no files are created/deleted and no files expanded.

HPSDMike
Valued Contributor

Re: MSA 2040 presenting one large volume

A volume should only be presented to multiple servers if those servers are part of a cluster and aware of each other. Typically like Windows server clustering, Hyper-V, or VMWare VMFS. I know you can do this in Linux with various cluster technologies but I'm not really up on the Linux clustering solutions. Also, though not always a hard requirement, you typically export the volume to the hosts as the same LUN# on each host. At minimum it helps with keeping track of things and might be tecnically required based on the clustering solution. 

I work for HPE. The comments in this post are my own and do not represent an official reply from the company. No warranty or guarantees of any kind are expressed in my reply.
jokken
Frequent Visitor

Re: MSA 2040 presenting one large volume

thanks guys. Good advice thank you. It has been suggested to me to use the ofcs2 filesystem on this (clustering/distributed filesystem)

http://www.oracle.com/us/technologies/linux/025995.htm

I don't know how to use it yet but from what was explained I'll have an ocfs2 server controlling the whole 7TB volume then multiple servers will be able to access it via FC lun if they each run ocfs2-tools. thanks!

 

HPSDMike
Valued Contributor

Re: MSA 2040 presenting one large volume

Just keep in mind that, especially as you start talking clustered solutions, you'll want to ensure you are following the tested/supported matrix for the MSA. If you look on HPE SPOCK, you can dive deep into what versions of OS's and clustered systems are supported with various MSA configs. 

https://h20272.www2.hpe.com/spock/

I work for HPE. The comments in this post are my own and do not represent an official reply from the company. No warranty or guarantees of any kind are expressed in my reply.