RAID 1/0 on Celerra NS20

Hi,

NS20, which is based on CX3 series does not support Raid 1/0. It supports Raid 1 instead.

The solution you mentioned is a general rule, but each model ( or series ) have their own supported configurations.

In your case, if you really needs mirroring, use two Raid 1 Raid Groups, then I recommend you to create your filesystems manually, and not using AVM.

The manual "Managing EMC Celerra Volumes and File Systems with Automatic Volume Management" available on powerlink has this table :

But, if you want to share, we can discuss the reasons do why you want to use Raid 1 on NAS.

Most NAS workloads have a read-to-write ratio heavily skewed toward reads, so the benefit of Raid 1 is rarely visible in a NAS context.

Gustavo Barreto.

with less than 5 disk drives, the only way to go is Raid 1

With your 4 drives, create 2 Raid 1 groups, and stripe your FS across them.

If I stripe the File System, can I still create a Storage Pool from it?  Or will I be stuck with just volumes?

I have NS20FC and was able to build the RAID1/0 with 4 disks. So it is supported.

Just make sure your disks are empty before you delete raid group and unbind your luns.

After you have done creating the raid you would need to rescan clariion in Celerra Manager and your pool will apear

Hope it helps

Hi,

It worked, but this does not mean that is "supported".

All documentation I consulted states Raid 1/0 is supported only on with two disks, and for CX4 and NX4 only.

This configuration might be "unsupported", even if it's technically possible.

Look this table :

Gustavo Barreto.

Article number emc138143 shows 2, 4, 6, or 8 disks as possible for RAID 10 so I'm not sure which document is the supported config.  But can we be in agreement that if I create 2 Raid 1's on the Clarion and stripe them in the Celerra ,  it will be the same peformance as a RAID10?  Correct me if I'm wrong but RAID 10 will be massive performance over RAID 5 correct?

Thanks!

Yes RAID 10 will definitely improve the performance. Example of applications would be mostly used for DBs such as exchange or SQL. best practices by Microsoft suggesting RAID 10 for db and RAID 1 for logs

techyranger schrieb: If I stripe the File System, can I still create a Storage Pool from it?  Or will I be stuck with just volumes?

I think you have some misconceptions about Celerra storage pools

they (system defined pools) are just a tool so that the system can recognize which dvols have similar performance characteristics so that AVM knows which dvols to use to build a file system. and yes - if it makes sense AVM will also stripe

If you are striping manually (MVM) then pools dont come into play - then its your responsibility which dvols (LUNs) should be used where

i.e. to avoid mistakes like striping onto the same raidgroup or only using LUNs from one storage processor, or ....

user-defined pools are a bit differently - there you should do your own striping and put stripes into the pool

but they really only make sense if you have lots of disks and want to make it easier for seperating them

either for performance or capacity - like one pool per department

a pool isnt a "hard" object like a raidgroup or an aggregrate (in another vendors speak)

if doesnt make a performance difference if a certain config is done via AVM with a pool or completely manual if the config is the same

hope that helps

Rainer