DL380 5i Controller Duplex Configuration

[Peter Staire]

I would like to setup the internal 5i controller for duplex operation with the following drive configurations - Drives: 0,1 RAID 0 (for OS) Drives: 2,3,4,RAID 5 (for application & data). Can anyone tell me if there is a significant performance gain using this configuration vs the stock simplex setup? Also, are there any drawbacks besides losing the external SCSI connection?

[JohnWRuffo]

Duplex: The benefit is you gian an extra SCSI channel to the data drives. You can segrigate the I/O some with this configuration.

Another config would be:

: Drives: 0, 1, 2, 3 = RAID 5
(duplexed using two channels instead of one)

: Drives 4 and 5 for the O/S.

While this config sets the O/S and swap (as if you were on a simplex cage) on the same channel as the data, it does provide "two SCSI channels" to the critical data drive as opposed to the "one" you suggested. Just an option to consider.

Are there any con's to duplexing other than loosing a VHDCI port on the rear of the box?

NO; Not in my opinion.

If you were to need an external port for a tape device, I would "highly recommend" you purchase a U320 SCSI HBA for that purpose and keep the I/O to tape and disk separate.

Duplexing should offer better performance than simplex configs.

[Peter Staire]

John, thank you for timely and informative reply. Regarding you suggested duplex configuration, I must be missing something in my understanding of the controller/drive operation. I was under the impression that with the duplex configuration, drives 0,1 would be assigned to channel 1 and drives 2,3,4,5 would be assigned to channel 2. I don't quite see how drives 0,1,2,3 (as in your suggestion) would be assigned to both channels. Any clarification you could render on this would be greatly appreciated.

[Oleg Koroz]

Yes Channel 2 with Duplex takes only ID0 and ID1 , Channel 1 will do for ID's 2-5 if you do have 5300 to use with data drive, recommended 15%-35% more performance

[Peter Staire]

Thanks, So what I was missing in the previous post was the suggested configuration would entail using a second SCSI controller along with the onboard 5i controller. Is this correct?

[Oleg Koroz]

Just as Optional suggestion, not mandatory depend what load takes DATA Drives. Always can be implemented in the feature. Also Optional BBWC can be used with 5i controller for READ/WRITE Settings.

http://h20000.www2.hp.com/bc/docs/support/UCR/SupportManual/TPM_266328-001_rev1_us/TPM_266328-001_rev1_us.pdf

[JohnWRuffo]

No... When you duplex the cage, all you are doing is adding the second channel of the 5i. It is still the same controller.
You just move the boot drives to bay 4 and 5 (mirror)
When you build the arrays, you make Array A (boot) on disk ID's 4 and 5. Array B is SCSI ID 0, 1, 2 & 3. In effect you have spread the I/O over both internal channels for your RAID 5.

We do it here but use RAID 1+0 instead of RAID5.

take a look at the attached visio logical view of what I am talking about.

[Oleg Koroz]

Summary

Option 1.
Use O/S Drives in ID4 and ID5 with Split I/O

Option 2.
Use O/S in ID0 and ID1 and four other drives at channel 1
BBWC Optional

Option 3.
Use additional controller as 5300 for Data Drives, keep Backplane as duplex.