EVA5K: Can Rack2 be expanded to 0C12D (168 Disks?)

[Alzhy]

And what needs to be purchased aside from the Disk shelves, etc?

[Luk Vandenbussche]

This are the parts no connect the shelfs between the two racks

336881-B21 - CANbus cab-to-cab cable
345580-B21 - Cable Kit,Expansion Cab Drive Shelf (one for each extra disk shelf)

[Mike Naime]

The maximum amount of drives that you can put behind one EVAxxxx controller is 240 drives. This can be done in a total of 18 shelves. (2C18D) If you have 3 cabinets, you can get 2 full 2C18D configurations in that floor space.

Now the thing to watch out for is if you have enough bandwidth to actually use all of that storage space without oversubscribing your storage ports. I do not recommend a frame of larger than 2C12D due to performance considerations.

Your situation may be different from mine. but we use up 90-95% occupancy on all of our EVA frames. (They are used for backup space) Because of this we are better of having 3 2C12D's as compared to 2 2C18d's.

Mike

[Alzhy]

Well right now our EVA5Ks are:

Rack1: 2C12D (168Disks - a mix of 72/146GBFC)
Rack2: 0C4D (48 FATA500 Disks)

So how can we possibly expand? Can we actually increase Rack2 to 0C12D? Our usage of the EVAs are mostly light duty and the FATA Diskgroups are used as VxVM Flashsnap sets.

BTW, what's the maximum number of VDISKS that can be carved on the EVA5Ks? Is their an increase on the 512 max (which I thought is the current limit @ VCS 3.028) with VCS 4.004?

Thanks!

[Paul Henderson_2]

We're doing the same expansion in the next few months, and from what I understand, you can connect a fully populated 2C12D rack (12 shelves of 14 disks), and hook it to a second rack with 6 shelves (0C6D). That is the maximum configuration (240 disks).

There is a bus line into which each disk shelf connects. The 2C12D rack's bus line has a terminator on the end. That terminator is removed, and another length strung over to the new 0C6D cabinet to attach the next 6 shelves. The top of that cabinet (6 shelves) remains empty.

The next expansion is to add a third cabinet, a 2CD12 with its own controllers, and expand its capacity into the empty top space of the 0C6D in the middle second cabinet.

[Daniel Smith_7]

I have a question kind of related to this, I'm currently about to put FATA disks into an EVA8000 which is currently in 2C8D config full of SCSI 146Gb 15K's. I have 2 shelves to add.

My questions is this: Am I better keeping the FATA all on the two new shelves or should I ungroup some of the SCSI from each of the current shelves, put them in the new shelves and fill up the slots in the existing shelves with FATA disks so i end up with each shelf having some SCSI and some FATA on it (in separated disk groups)?

[Paul Henderson_2]

We've also added two shelves of FATA to an EVA with all other shelves fiber, and the recommendation was to NOT mix fiber and FATA on the same shelf.

Also, very important... put the FATA into their own disk group so that you are not penalizing the performance of the fiber disks.

The way we have it configured, we have two disk groups, one default, the other archival, and the default has all the fiber disks, the archival (we do disk to disk backups) is all the FATA disks.

[Tom O'Toole]

Mike,

Are you referring to port oversubscription on the back end (too many simultaneous disk transfers for the loops), or on the host side (as a result of more storage=more use of that storage)?

[Uwe Zessin]

> what's the maximum number of VDISKS that can be carved on the EVA5Ks?

The user guide from March 2006 says:
""The EVA5000 provides:
* Up to 32 TB of usable capacity. [I've explained this a few times already in different thraeds] Total maximum raw capacity will vary based upon the
redundancy (Vraid) selected.
* A maximum of 240 disk drives
* Support for 1024 virtual disks
""


> The maximum amount of drives that you can put behind one EVAxxxx controller is 240 drives.



> Am I better keeping the FATA all on the two new shelves

No, spread all disks (types) equally across the shelves.


> some SCSI and some FATA

Nit pick: both the "FC disks" and the "FATA disks" use serial SCSI protocol - it is the same interface, the FATA mechanics are a bit slower.


> Also, very important... put the FATA into their own disk group so that you are not penalizing the performance of the fiber disks.

As far as I can tell, Command View does not allow you to mix.
But I think you might penalize performance anyway, because at least one of the quorum disks will go into the FATA group!