I recall from mixing 9s and 18s at a customer site that you *can* add the 18s to an existing volume of 9s and still get 18G worth (minus filesystem overhead, snaps, etc.) from each 18G drive. The first 18G drive becomes parity and the 9G parity becomes a data drive (so you get 9G additional capacity from the first 18G drive), but after that you should get 18 and not 9. Historically, you've been able to mix and match with the filer doing the right thing. It is true that if a 9G drive fails and there is no 9G spare, it will rebuild on an 18G drive but you will only get 9G on that rebuilt drive. So be sure to have a spare of each size available. If anybody has tested this with different results I could be completely nuts, so please educate us!

It is important to make the 9G shelves the lowest order shelves for FCAL loop initialization purposes, so make the 9G shelves numbers 0 and 1.

Regards, Arnie

-----Original Message----- From: Mohler, Jeff [mailto:jeff.mohler@netapp.com] Sent: Thursday, October 07, 1999 11:38 AM To: 'Jason Middlebrooks'; toasters@mathworks.com Subject: RE: Max number of drives.

Sure, no problem.

But when you add them to a volume (if you are not creating a new one) make sure you add them to the volume made up of 18G drives. (That is, if the 18G drives are a separate volume from the 9G ones).

If you mix/max drive sizes in a volume, the larger drives will appear only to be the size of the smallest drive in the array.

-----Original Message----- From: Jason Middlebrooks [mailto:Jason_Middlebrooks@datalink.com] Sent: Thursday, October 07, 1999 12:01 PM To: toasters@mathworks.com Subject: Max number of drives.

Question.

I have 14 9Gig drives and 14 18Gig drives. So a total of 28 drives. Can I add 7 more 18Gig drives on the same loop?

The filer is a F760

Thanks in advance Jason Middlebrooks