topic Re: Raid 4Si question in Disk Enclosures

Raid 4Si question

Vincent Farrugia — Fri, 13 May 2005 02:45:39 GMT

Hello,

My customer just bought an rp5470 with a Raid 4Si card installed, connected to a DS2300 with 1 controller with 5 146Gb disks in full bus mode using only 1 controller from the Raid 4Si card.

We would like to make a RAID 1 + 0 LUN using 4 of the 5 disks on the DS2300. I know that to do this, you need to span across arrays. What I did (since I do not have more than 1 controller on the ds2300, so split-bus mode is not an option) is to create 2 RAID 1 LUNS containing 2 disks each and on one of the LUNs I enabled spanning. The Raid 4si seemed happy with this config, and immediately the size of the LUN increased from 146 to 292Gb, so far so good.

However, I tried to dd on the device file created by the LUN and only disk 1 and disk 3 are flashing, not all 4 disks. I assume that to span, you need to span across controllers, but I tried to span using this method. Is it ok? or I need an additional controller on the ds2300 and put it in split-bus mode?

Please help me, points will be rewarded.

Vince

Re: Raid 4Si question

Leif Halvarsson_2 — Fri, 13 May 2005 06:14:42 GMT

Hi,
Did you use dd for reading or writing to the disks ? If reading, it is not necessary with activity on all disks. On the other hand, if writing, all disks should be active if everything is OK.

I have no experience with your specific harware but I don't understand why it should not be possible to create a RAID 1+0 direct, using 1 or both of the SCSI controllers (buses) on the 4Si.

And, what do you mean with "controlers" for the DS2300. Is not the DS2300 a JBOD ?

Re: Raid 4Si question

Vincent Farrugia — Fri, 13 May 2005 06:30:39 GMT

Hello,

I only read to null using dd, I didn't write, I will check that.

By controllers I mean that the ds2300 comes with either 1 or 2 controllers (for fullbus/splitbus config). I have only 1 controller in mine.

Thanks,
Vince

Re: Raid 4Si question

Ron Lawson_1 — Wed, 18 May 2005 18:05:00 GMT

Assuming you aren't using production data, you could pull one of the flashing drives and see if its mirrored pair starts flashing.

Re: Raid 4Si question

Vincent Farrugia — Fri, 20 May 2005 01:43:15 GMT

Thanks for all your help. I tried writing loads of data to the LUN and all 4 disks were flashing.

Case is closed

Vince