P2000 MSA 2000 G3 maximum disks to present?

[GERT GOOSSENS]

Hi guys, I need your help to understand how many controllers I need.... for this project I am working on. I am going for a P2000 MSA 2000 G3 with 71 disks LFF 1TB (this choice is made by management). We will use this as "DAS"-storage, meaning, 1 physical disk must be presented as LUN to the server - so we need to present 71 LUN's... No RAID, no virtual disks are needed but...

Based on the G2 best practices, there I read and I quote: The HP StorageWorks MSA2000 G2 system can have a maximum of 16 virtual disks per controller for a maximum of 32 virtual disks with a dual controller configuration.

Now G2 - if I get it sorted out - needs one virtual disk mapped to one physical disk and this is limited to 16 disks per controller... so I need 5 controllers (10 for redundancy)... etc...

For G3 - I do not find any info about this... is it correct I can directly access the disks using LUN's (then 512 is the max)... or do I have the same limitation? Remember, no RAID config will be used... we need to access the disks directly.

Can somebody sort me out based on experience? No presales stuff, but real world experience?

Thank you very much in advance....

Regards,

Gert

[Torsten.]

I really wonder why you want to have such "DAS" like storage configuration.

I don't understand why you want to present real physical dedicated disks instead of any kind of striped LUNs (even in RAID 0) - which would probably be much faster.

Even for a real direct attached storage (e.g. D2600 or D2700, older MSA70, etc) you would use a smartarray controller and any kind of striped LUN).

Please clarify.

[Johan Guldmyr]

Some filesystems (ZFS) prefer to have "JBOD" or straight-through and complete access to the disk.

If that is the reason, are you sure that you want to do it this way? I haven't done this with a P2000 G3 but with a D2600/P411 and the performance (without openindiana tuning) was identical with or without hw raid.

To me it sounds like it could / would cause a lot of headache when a disk breaks (recreate vdisk, new device on server, add that to raid on server)? Shouldn't these reasons also be part of management decisions?

[GERT GOOSSENS]

In fact, it is a setup for Exchange 2010 DAG environment. A breakdown of one disk is an autmatic failover of the DB on it. Therefore... no virtual disks with more than one physical disk.

Now, this decision has been made up by management and I am afraid changing is not the aim. I am only concerned about the controllers... If I want to present the 71 disks over 5 servers where one physical disk = one LUN (must it be via Virtual disk)... what's the story about the controllers? Is this limited to only 16 per controller? That is not clear to me and it makes part of how many (dual) controllers we have to order... any experience?

Thanks.

[hvhari]

MSA P2000 G3 has the limitation of maximum 512 Luns per MSA. You can have maximum of only two controllers for an MSA.

Refer page 37 in the user guide :  http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02254382/c02254382.pdf

You can also use the SMU to view the configuration limits. Refer page 89-90 of SMU guide

http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c02520791/c02520791.pdf

[Torsten.]

This does not sound like a perfect solution to me.

You want to build a high availability solution based on a single array with non-protected data volumes?

This creates multiple single points of failure.

In addition the configuration limits prevents your planned configuration.

I'm not an expert of this exchange solution, but maybe another kind of storage (e.g. a HP Lefthand P4x00 cluster) would be a better solution for you?