You can add 36s and 18s in the same volume. If you add them to the same RAID group, the *first* 36GB disk becomes the parity(needed for the extra stripes) and the 18GB parity becomes a data drive(they flip roles).

However, it is in my opinion, better to just simply make a new RAID group with the 36GB disks.

They will be taken fully advantage of (i.e. they will be 36GB disks).

However, if your current volume is a Zoned Checksum volume, and you add the new 36GB(34F) disks, you will lose the benefits of the BCS disks and they will work like Zoned checksum disks. Chances are your current 18GB disks do not have the little yellow labels and are ZCS.

So you may want to create a new volume with the 36GB disks unless they are BCS disks already.

This is perfectly legal, it has been being done for a long time now. (mixing drives of varying sizes). The one thing to remember, the largest disk in the RAID group is *always* the parity disk, unless of course they are all the same size in the RAID group.

--tmac

Timothy A. McCarthy System Engineer Network Appliance Federal Systems INC. http://www.netapp.com http://www.netapp.com 410-290-1581 Office Page Me at: 877-5-NETAPP

--> -----Original Message----- --> From: White, Lance [mailto:Lance.White@netapp.com] --> Sent: Friday, October 19, 2001 2:34 PM --> To: 'Viper Rinspeed'; toasters@mathworks.com --> Subject: RE: Netapp hardware --> --> --> 1)Yes...but you won't want to do this for an extended --> period as you'll only be using half of the 36GB as a spare --> if an 18GB drive fails. Hence, when you get your --> replacement 18GB drive, simply replace the failed 18GB --> drive (new drive will show up as a spare), then MANUALLY --> fail the 36GB drive so that the 18GB reclaims the role, and --> 36GB goes back into the spares pool. --> 2) Same issue as above...the 36GB drives will essentially --> become 18GB drives. Rather wasteful. You CAN do this, but --> you probably won't want to. --> 3) Not a performance or reliability issue...more of a --> "digital waste" issue. --> --> -----Original Message----- --> From: Viper Rinspeed [mailto:debian22@yahoo.fr] --> Sent: Friday, October 19, 2001 11:19 AM --> To: toasters@mathworks.com --> Subject: Netapp hardware --> --> --> Hi, --> --> We have a Netapp 740 with a FC9 shelf (18Gb disks). --> We are planning to get a DS14 shelf with 36Gb disks. --> I have two questions: --> 1- Can we use only one spare disk (36Gb disk) instead of two --> (1 18Gb and 1 36Gb)? Will the spare 36Gb disk be used correctly --> to replace a failed 18Gb disk ? --> 2- Can I mix 18Gb and 36Gb disks in the same volume (same RAID)? --> If yes, how the data will be written? Let's say, I have --> 2x18G+2x36Gb (+parity). --> Will the 36Gb disks stored twice more data than the 18Gb ? --> Is there a performance issue ? a reliability issue (more --> data written-> more --> risk of failure?) ? --> --> Thank you very much. --> --> Jn --> --> --> ___________________________________________________________ --> Un nouveau Nokia Game commence. --> Allez sur http://fr.yahoo.com/nokiagame avant le 3 novembre --> pour participer à cette aventure tous médias. -->