topic Expanding array in DL380 in Disk Enclosures

Expanding array in DL380

Andrew_271 — Wed, 09 May 2007 07:43:44 GMT

I have a DL380. One of our arrays contains six 299.9 GB drives. I want to expand this array with about 14 additional drives.

In testing, I had an older HP server with a 5i controller. I had three 72GB disks in Raid 5, and when I expanded it to include a 4th, it took almost 3 days for the expansion to complete (with the controller having "expand priority" set to high.

The DL380 I want to do the real expansion on has a 6i controller.

Can i expect similar results, or should I expect this to take weeks?

Re: Expanding array in DL380

Rob Leadbeater — Wed, 09 May 2007 12:03:55 GMT

Hi,

I've never tried it, but that sounds like a long time...

Do you have a BBWC module (Battery Backed Write Cache) installed on your servers ?

That *might* have an effect on the expansion time...

Cheers,

Rob

Re: Expanding array in DL380

Steven Clementi — Wed, 09 May 2007 13:25:04 GMT

It shouldn't take many weeks, but it can take a couple.

the time it takes depends on a few things...

1. how much data you actually have stored on the existing array.

2. i/o level to that data.

In the ideal situation, it should take 15 minutes per GB worth of data, assuming you had 6 300GB drives in RAID5, @1.5TB usable and you have 1TB of data... the expansion would take @10 and a half days to complete... theoretically. Since you will have periods of usage on the system, you will need to add some time due to the controller doing double duty... expanding and serving up data.

The short story is... it's going to take a while to expand and will not happen overnight.

The BBWC will probaby help too.

Steven

Re: Expanding array in DL380

Andrew_271 — Wed, 09 May 2007 13:39:53 GMT

I can deal with it taking a while....couple questions though.

If a drive fails during the expansion, and a hotspare kicks in, what happens?

What if for some reason we lose power or the server reboots during the expansion?

This is the info i have regarding a battery...i assume this means we have it?

Array Accelerator
Present Yes
Cache Status Enabled
Accelerator Ratio 50% Read /50% Write
Total Memory on Controller 192 MB
Battery Pack Count 2
Battery Status OK

Re: Expanding array in DL380

Andrew_271 — Thu, 10 May 2007 07:30:35 GMT

One other thing - how much impact on day-to-day i/o will putting the Expand Priority to High?

Can this setting be changed during the expand?

Also - I thuoght there was a 6i controller in this server, it's a Smart Array 6400 - that make a difference?