Hardware RAID

[Eugeny Brychkov]

Mike,
in FC60 when you create LUN you tell disk array which RAID level it will be. For example, you create LUN 0 of RAID 1 with disks in SC10-0 and SC10-1, and LUN 1 with disks in SC10-2 and SC10-3 etc and at the same time you can create LUN 2 of RAID 5 with 4 disks from all 4 SC10s. Just an example.
There's important note: when you create LUN use disks installed in different SC10 enclosures. In case one enclosure fill fail completely you'll have redundancy loss, not data loss
Eugeny

[Pete Randall]

Mike,

The third SC10 is also part of the FC60. It originally contained just the first two SC10s which were configured as RAID0/1 (mirrored and striped). Later, we added the third SC10 which we wanted to use for our development copy of the database (we share this FC60 between two non-ServiceGuard servers - definitely unsupported, don't tell anybody). Since we needed to fit 180GB of mirrored data (occupying 360GB of space) into just 180GB, we chose to use RAID5, which gave us 144GB of useable space (obviously we had trim a little extraneous data but we made it fit).

That's the difference between RAID0/1 and RAID5. The RAID0/1 configuration gives the most protection and performance. The RAID5 gives the most storage efficiency while sacrificing some protection and some performance.


Pete

[Mike Fisher_5]

Eugeny & Pete

Thank you - It makes sense now
Not applicable to this client,
but useful for something else that I have in mind

Mike "2hrs 56mins from The Gate" Fisher