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Adding HD's to existing Logical Drive

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David Klein_2
Occasional Contributor

Adding HD's to existing Logical Drive

Hello,

I was wondering if someone could provide me with some advice/information re: HP NetRAID controllers and if there are any limits to the number of drives that can be added to a Logical Drive/Array. I have reviewed HP's documentation on configuring NetRAID controllers and it indicated that the drive stripes only had an effect on performance, but didn't mention anything about a minimum stripe size for dynamically adding capacity.

When I attempted to add an extra drive to an existing logical drive on our LXr Pro, I encountered a message indicating that "Maximum STRIPE number reached".

Here's the config information:

Software (on NT 4.0 Server): NetRAID Assistant V 1.02.02
Hardware: HP NetServer LXr Pro + NetServer Rack Storage /8

Stripe size on LD1 is 8K Bytes
#stripes: 8

Configuration:

The two physical drives I want to add to the logical drive are on Channel 0 (as #10 and #11).
The Logical Device is Array 1, LD1:RAID5:60738MB

When attempting to add capacity, NetRAID assistant asks:

Add selected physical drive(s) to selected Logical Drive?

This then results in a message "Maximum STRIPE number reached".

Having read the other messages here, it *seems* that I would have to wipe the existing partition and then up the stripe size to 64K. Does anyone know a way around this, or is it actually necessary in this case?

Much obliged,

Dave.
1 REPLY
Marco Hogeveen
Honored Contributor
Solution

Re: Adding HD's to existing Logical Drive

David,

Unfortunately the maximum stripe number has nothing to do with the stripe size, but with the number of disks (stripes) in a RAID5.
The maximum number of disks for this type of netraid in a RAID5 is 8.
If you want a bigger logical drive, the only thing you can do is create a RAID50 (span 2 RAID5's) .
The disadvantage is that you have to clear the onfiguration first (so you loose all your data).
Another disadvantage of a RAID50 is that you're using 2 drives for redundancy, instead of 1 in a RAID5 so you're using less of your netto capacity.

Good luck,

Marco.