RAID10 with MegaRAID WebBIOS

Question

I'm trying to create two RAID10 arrays using LSI MegaRAID's WebBIOS utility.

If I understand correctly, I must create many two-disk RAID1 pairs called "disk groups" and then span those disk groups together to get the striping layer. Then I can afford to lose one drive from every two-drive RAID1 disk group without suffering a data loss. Right?

The problem is that I have 10 SSD drives and 10 SAS drives. But I can only create 8 disk groups. That's 16 drives. What gives? Will I have to settle for RAID01 creating 5-drive RAID0 and mirroring it with another such array?

Controller: Supermicro AOC-USAS2LP-H8iR (LSI 2108 chip)

Solution

For a RAID-10 of 20 drives (for example): 2 'groups' of 10 drives (2 RAID-1 'mirrors', 5 drives per side in each mirror), striped (RAID-0).

See here for some info that may help clarify your options.

Perhaps 2 RAID-10's made from 9-drive, 3-way RAID-1's, with a hot spare (the 10th drive) for each RAID-10? :)

Comments

[Henno]

I know what RAID10 is. The problem is that the WebBIOS utility is preventing me from adding more than 8 drive groups. I created 5 drive groups (of 2 drives each) and then I created RAID0 span over those 5 drivegroups. All was fine. But I could not repeat that process to create a second RAID10 array: the utility hid the button to create a new data group after there was already 8 datagroups.

[Henno]

We revisited WebBIOS once more and this time we were able to create five disk groups, add them to a span and make that RAID10. Then we selected configuartion wizard, add, manual and redid. This time we could create more than 8 disk groups. Perhaps we missed something obvious last time.

[Henno]

Related topic you may find interesting: serverfault.com/questions/517729/…